Abrasive particles having complex shapes and methods of forming same

ABSTRACT

An abrasive grain is disclosed and may include a body. The body may define a length (l), a height (h), and a width (w). In a particular aspect, the length is greater than or equal to the height and the height is greater than or equal to the width. Further, in a particular aspect, the body may include a primary aspect ratio defined by the ratio of length:height of at least about 2:1. The body may also include an upright orientation probability of at least about 50%.

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application claims priority from U.S. Provisional PatentApplication No. 61/584,998, filed Jan. 10, 2012, entitled “ABRASIVEPARTICLES HAVING COMPLEX SHAPES AND METHODS OF FORMING SAME” naminginventor Doruk O. Yener et al., which application is incorporated byreference herein in its entirety.

FIELD OF THE DISCLOSURE

This disclosure, in general, relates to methods and systems for formingstructured abrasive articles. More particularly, this disclosure relatesto shaped abrasive grains.

BACKGROUND

Abrasive articles, such as coated abrasives and bonded abrasives, areused in various industries to machine workpieces, such as by lapping,grinding, or polishing. Machining utilizing abrasive articles spans awide industrial scope from optics industries, automotive paint repairindustries, to metal fabrication industries. In each of these examples,manufacturing facilities use abrasives to remove bulk material or affectsurface characteristics of products.

Surface characteristics include shine, texture, and uniformity. Forexample, manufacturers of metal components use abrasive articles to fineand polish surfaces, and oftentimes desire a uniformly smooth surface.Similarly, optics manufacturers desire abrasive articles that producedefect free surfaces to prevent light diffraction and scattering.

Manufactures also desire abrasive articles that have a high stockremoval rate for certain applications. However, there is often atrade-off between removal rate and surface quality. Finer grain abrasivearticles typically produce smoother surfaces, yet have lower stockremoval rates. Lower stock removal rates lead to slower production andincreased cost.

Particularly in the context of coated abrasive articles, manufactures ofabrasive articles have introduced surface structures to improve stockremoval rate, while maintaining surface quality. Coated abrasivearticles having surface structures or patterns of raised abrasivelayers, often called engineered or structured abrasives, typicallyexhibit improved useful life.

However, typical techniques for forming structured abrasive articles areunreliable and suffer from performance limitations. A typical processfor forming a structured abrasive article includes coating a backingwith a viscous binder, coating the viscous binder with a functionalpowder, and stamping or rolling structure patterns into the viscousbinder. The functional powder prevents the binder from sticking topatterning tools. The binder is subsequently cured.

Imperfect coating of the viscous binder with functional powder leads tobinder sticking on patterning tools. Binder sticking produces poorstructures, leading to poor product performance and wasted product.

Selection of binders appropriate for typical structured abrasiveformation techniques is limited by the process. Typical binders includehigh loading of traditional fillers that increase the viscosity of thebinder. Such traditional fillers affect the mechanical characteristicsof the binder. For example, high loading of traditional fillers mayadversely affect tensile strength, tensile modulus, and elongation atbreak characteristics of the binder. Poor mechanical characteristics ofthe binder allow for loss of abrasive grains, leading to scratching andhaze on surfaces and reducing abrasive article life.

Loss of grains also degrades the performance of abrasive articles,leading to frequent replacement. Frequent abrasive article replacementis costly to manufacturers. As such, improved abrasive articles andmethods for manufacturing abrasive articles would be desirable.

SUMMARY

An abrasive grain is disclosed and may include a body. The body maydefine a length (l), a height (h), and a width (w). In a particularaspect, the length is greater than or equal to the height and the heightis greater than or equal to the width. Further, in a particular aspect,the body may include a primary aspect ratio defined by the ratio oflength:height of at least about 1:1. The body may also include anupright orientation probability of at least about 50%.

In another aspect, an abrasive grain is disclosed and may include a bodythat has a length (l), a width (w), and a height (h). The length, width,and height may correspond to a longitudinal axis, a lateral axis, and avertical axis, respectively, and the longitudinal axis, lateral axis,and vertical axis may define three perpendicular planes. In this aspect,the body may include an asymmetric geometry with respect to any of thethree perpendicular planes.

In yet another aspect, an abrasive grain is disclosed and may include abody having a complex three-dimensional geometry including 3-foldsymmetry in three perpendicular planes defined by a longitudinal axis, alateral axis, and a vertical axis. Further, the body may include anopening that extends through the entire interior of the body along oneof the longitudinal axis, lateral axis, or vertical axis.

In still another aspect, an abrasive grain is disclosed and may includea body having a complex three-dimensional geometry defined by a length(l), a width (w), and a height (h). The body may also include a centerof mass and a geometric midpoint. The center of mass may be displacedfrom the geometric midpoint by a distance (D_(h)) of at least about0.05(h) along a vertical axis of the body defining the height.

In another aspect, an abrasive grain is disclosed and may include a bodythat defines a length (l), a width (w), and a height (h). The body mayinclude a base surface and an upper surface. Further, the base surfacecomprises a different cross-sectional shape than a cross-sectional shapeof the upper surface.

In still another aspect, an abrasive grain is disclosed and may includea body that has a generally flat bottom and a dome shaped top extendingfrom the generally flat bottom.

In another aspect, an abrasive grain is disclosed and may include a bodycomprising a length (l), a width (w), and a height (h). The length,width, and height may correspond to a longitudinal axis, a lateral axis,and a vertical axis, respectively. Further, the body may include a twistalong a longitudinal axis defining the length of the body such that abase surface is rotated with respect to an upper surface to establish atwist angle.

In yet another aspect, an abrasive grain is disclosed and may include abody having a first end face and a second end face a, at least threeadjacent side faces extending between the first end face and the secondend face, and an edge structure established between each pair ofadjacent side faces.

In another aspect, an abrasive grain is disclosed and may include a bodyhaving a central portion and at least three radial arms extendingoutwardly from the central portion along the entire length of thecentral portion.

In yet another aspect, an abrasive grain includes a body having a length(l), a width (w), and a height (h), wherein the body has a base surfaceend and an upper surface, and wherein the base surface includes adifferent cross-sectional shape than a cross-sectional shape of theupper surface.

For another aspect, an abrasive grain includes a body having a centralportion and at least three radial arms extending outwardly from thecentral portion along the entire length of the central portion, whereineach radial arm includes an arrow shaped distal end.

According to another aspect, a shaped abrasive particle includes a bodyhaving a length (l), a width (w), and a height (h), wherein the bodycomprises a base surface end, an upper surface, and a side surfaceextending between the base surface and the upper surface, and whereinthe base surface has a different cross-sectional shape than across-sectional shape of the upper surface.

In one aspect, a shaped abrasive particle includes a body having alength (l), a width (w), and a height (h), wherein the body has athree-pointed star including a first arm defining a first arm, a secondarm defining a second arm, and a third arm defining a second arm, andwherein the first arm, second arm and third arm define a total angle ofless than about 180 degrees, and wherein the body has a curling factorof not greater than about 10.

For another aspect, a shaped abrasive particle includes a body having alength (l), a width (w), and a height (h), wherein the body defines afour-pointed star having a first arm, second arm, third arm, and fourtharm extending from a central portion, and wherein the body has a curlingfactor of not greater than about 10.

According to yet another aspect, a shaped abrasive particle includes abody having a length (l), a width (w), and a height (h), wherein thebody is defined by a base surface, an upper surface, and a side surfaceextending between the base surface and the upper surface, wherein thebase surface comprises a cross shaped two-dimensional shape and theupper surface comprises a rounded quadrilateral two-dimensional shape.

For still another aspect, a shaped abrasive particle includes a bodyhaving a first layer having a first length and a second layer overlyingthe first layer, wherein the second layer has a length that is within arange between about 50% and about 90% of the length of the first layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure may be better understood, and its numerousfeatures and advantages made apparent to those skilled in the art byreferencing the accompanying drawings.

FIG. 1 is a diagram of an exemplary process;

FIG. 2 is a perspective view of a structured abrasive article;

FIG. 3 is a perspective view of a first embodiment of a shaped abrasivegrain;

FIG. 4 is a plan view of a second end the first embodiment of a shapedabrasive grain;

FIG. 5 is a perspective view of a second embodiment of a shaped abrasivegrain;

FIG. 6 is a plan view of a second end face of the second embodiment of ashaped abrasive grain;

FIG. 7 is a perspective view of a third embodiment of a shaped abrasivegrain;

FIG. 8 is a plan view of a second end face of the first embodiment of ashaped abrasive grain;

FIG. 9 is a perspective view of a fourth embodiment of a shaped abrasivegrain;

FIG. 10 is a plan view of a second end face of the fourth embodiment ofa shaped abrasive grain;

FIG. 11 is a perspective view of a fifth embodiment of a shaped abrasivegrain;

FIG. 12 is a plan view of a bottom of the fifth embodiment of a shapedabrasive grain;

FIG. 13 is a perspective view of a sixth embodiment of a shaped abrasivegrain;

FIG. 14 is a plan view of a second end face of the fourth embodiment ofa shaped abrasive grain;

FIG. 15 is a plan view of a top of a seventh embodiment of a shapedabrasive grain;

FIG. 16 is a plan view of a bottom of the seventh embodiment of a shapedabrasive grain;

FIG. 17 is a plan view of a top of an eighth embodiment of a shapedabrasive grain;

FIG. 18 is a plan view of a bottom of the eighth embodiment of a shapedabrasive grain;

FIG. 19 is a perspective view of a ninth embodiment of a shaped abrasivegrain;

FIG. 20 is a plan view of a second end face of the ninth embodiment of ashaped abrasive grain;

FIG. 21 is a perspective view of a tenth embodiment of a shaped abrasivegrain;

FIG. 22 is a plan view of a first end face of the tenth embodiment of ashaped abrasive grain;

FIG. 23 is a plan view of a second end face of the tenth embodiment of ashaped abrasive grain;

FIG. 24 is a perspective view of an eleventh embodiment of a shapedabrasive grain;

FIG. 25 is a plan view of a second end face of the eleventh embodimentof a shaped abrasive grain;

FIG. 26 is a perspective view of a twelfth embodiment of a shapedabrasive grain;

FIG. 27 is a plan view of a second end face of the twelfth embodiment ofa shaped abrasive grain;

FIG. 28 is a perspective view of a thirteenth embodiment of a shapedabrasive grain;

FIG. 29 is a plan view of a second end face of the thirteenth embodimentof a shaped abrasive grain;

FIG. 30 is a perspective view of a fourteenth embodiment of a shapedabrasive grain;

FIG. 31 is a plan view of a second end face of the fourteenth embodimentof a shaped abrasive grain;

FIG. 32 is a perspective view of a fifteenth embodiment of a shapedabrasive grain;

FIG. 33 is a plan view of a second end face of the fifteenth embodimentof a shaped abrasive grain;

FIG. 34 is a perspective view of a sixteenth embodiment of a shapedabrasive grain;

FIG. 35 is a plan view of a second end face of the sixteenth embodimentof a shaped abrasive grain;

FIG. 36 is a perspective view of a seventeenth embodiment of a shapedabrasive grain;

FIG. 37 is a plan view of a second end face of the seventeenthembodiment of a shaped abrasive grain;

FIG. 38 is a perspective view of an eighteenth embodiment of a shapedabrasive grain;

FIG. 39 is a plan view of a second end face of the eighteenth embodimentof a shaped abrasive grain;

FIG. 40 is a perspective view of a nineteenth embodiment of a shapedabrasive grain;

FIG. 41 is a plan view of a second end face of the nineteenth embodimentof a shaped abrasive grain;

FIG. 42 is a perspective view of a twentieth embodiment of a shapedabrasive grain;

FIG. 43 is a plan view of a second end face of the twentieth embodimentof a shaped abrasive grain;

FIG. 44 is a perspective view of a twenty-first embodiment of a shapedabrasive grain;

FIG. 45 is a plan view of a first end face of the twenty-firstembodiment of a shaped abrasive grain;

FIG. 46 is a plan view of a second end face of the twenty-firstembodiment of a shaped abrasive grain;

FIG. 47 is a perspective view of a twenty-second embodiment of a shapedabrasive grain;

FIG. 48 is a plan view of a first end face of the twenty-secondembodiment of a shaped abrasive grain;

FIG. 49 is a plan view of a second end face of the twenty-secondembodiment of a shaped abrasive grain;

FIG. 50 is a perspective view of a twenty-third embodiment of a shapedabrasive grain;

FIG. 51 is a plan view of a first end face of the twenty-thirdembodiment of a shaped abrasive grain;

FIG. 52 is a plan view of a second end face of the twenty-thirdembodiment of a shaped abrasive grain;

FIG. 53 is a perspective view of a twenty-fourth embodiment of a shapedabrasive grain;

FIG. 54 is a plan view of a first end face of the twenty-fourthembodiment of a shaped abrasive grain;

FIG. 55 is a plan view of a second end face of the twenty-fourthembodiment of a shaped abrasive grain;

FIG. 56 is a perspective view of a twenty-fifth embodiment of a shapedabrasive grain;

FIG. 57 is a plan view of a first end face of the twenty-fifthembodiment of a shaped abrasive grain;

FIG. 58 is a plan view of a second end face of the twenty-fifthembodiment of a shaped abrasive grain;

FIG. 59 is a perspective view of a twenty-sixth embodiment of a shapedabrasive grain;

FIG. 60 is a plan view of a first end face of the twenty-sixthembodiment of a shaped abrasive grain; and

FIG. 61 is a plan view of a second end face of the twenty-sixthembodiment of a shaped abrasive grain.

FIGS. 62A and B includes illustrations of a system for forming shapedabrasive particles in accordance with an embodiment.

FIG. 63 includes an illustration of a system for forming a shapedabrasive particle in accordance with an embodiment.

FIG. 64 includes an illustration of a portion of a system for forming ashaped abrasive particle in accordance with an embodiment.

FIG. 65A includes an image of a shaped abrasive particle according to anembodiment.

FIG. 65B includes an illustration of a side view of the shaped abrasiveparticle of FIG. 65A.

FIG. 65C includes an image of a shaped abrasive particle according to anembodiment.

FIG. 66A includes an image of a shaped abrasive particle according to anembodiment.

FIG. 66B includes an illustration of a side view of the shaped abrasiveparticle of FIG. 66A.

The use of the same reference symbols in different drawings indicatessimilar or identical items.

DETAILED DESCRIPTION

The following is also directed to methods of forming shaped abrasiveparticles and features of such shaped abrasive particles. The shapedabrasive particles may be used in various abrasive articles, includingfor example bonded abrasive articles, coated abrasive articles, and thelike. Alternatively, the shaped abrasive particles of the embodimentsherein may be utilized in free abrasive technologies, including forexample grinding and/or polishing slurries.

Referring initially to FIG. 1, an exemplary process is shown and isgenerally designated 100. As shown, a backing 102 may be paid from aroll 104. The backing 102 may be coated with a binder formulation 106dispensed from a coating apparatus 108. An exemplary coating apparatusincludes a drop die coater, a knife coater, a curtain coater, a vacuumdie coater or a die coater. Coating methodologies can include eithercontact or non contact methods. Such methods include 2 roll, 3 rollreverse, knife over roll, slot die, gravure, extrusion or spray coatingapplications.

In a particular embodiment, the binder formulation 106 may be providedin a slurry that includes the binder formulation and abrasive grains. Inan alternative embodiment, the binder formulation 106 may be dispensedseparate from the abrasive grains. Then, the abrasive grains may beprovided following the coating of the backing 102 with the binderformulation 106, after partial curing of the binder formulation 106,after patterning of the binder formulation 106, or after fully curingthe binder formulation 108. The abrasive grains may, for example, beapplied by a technique, such as electrostatic coating, drop coating ormechanical projection. In a particular aspect, the abrasive grains maybe any combination of one or more of the shaped abrasive grainsdescribed herein.

The binder formulation 106 may be cured after passing under an energysource 110. The selection of the energy source 110 may depend in partupon the chemistry of the binder formulation 106. For example, theenergy source 110 may be a source of thermal energy or actinic radiationenergy, such as electron beam, ultraviolet light, or visible light. Theamount of energy used may depend on the chemical nature of the reactivegroups in the precursor polymer constituents, as well as upon thethickness and density of the binder formulation 106. For thermal energy,an oven temperature of about 75.degree. C. to about 150.degree. C. andduration of about 5 minutes to about 60 minutes may be generallysufficient. Electron beam radiation or ionizing radiation may be used atan energy level of about 0.1 MRad to about 100 MRad, particularly at anenergy level of about 1 MRad to about 10 MRad. Ultraviolet radiationincludes radiation having a wavelength within a range of about 200nanometers to about 400 nanometers, particularly within a range of about250 nanometers to 400 nanometers. Visible radiation includes radiationhaving a wavelength within a range of about 400 nanometers to about 800nanometers, particularly in a range of about 400 nanometers to about 550nanometers. Curing parameters, such as exposure, are generallyformulation dependent and can be adjusted via lamp power and belt speed.

In an exemplary embodiment, the energy source 110 may provide actinicradiation to the coated backing, partially curing the binder formulation106. In another embodiment, the binder formulation 106 is thermallycurable and the energy source 110 may provide heat for thermaltreatment. In a further embodiment, the binder formulation 106 mayinclude actinic radiation curable and thermally curable components. Assuch, the binder formulation may be partially cured through one ofthermal and actinic radiation curing and cured to complete curingthrough a second of thermal and actinic radiation curing. For example,an epoxy constituent of the binder formulation may be partially curedusing ultraviolet electromagnetic radiation and an acrylic constituentof the binder formulation may be further cured through thermal curing.

Once the binder formulation 106 is cured a structured abrasive article112 is formed. Alternatively, a size coat may be applied over thepatterned abrasive structures. In a particular embodiment, thestructured abrasive article 112 may be rolled into a roll 114. In otherembodiments, fully curing may be performed after rolling a partiallycured abrasive article 112.

In one or more alternative embodiments, a size coat may be applied overthe binder formulation 106 and abrasive grains. For example, the sizecoat may be applied before partially curing the binder formulation 106,after partially curing the binder formulation 106 or after furthercuring the binder formulation 106. The size coat may be applied, forexample, by roll coating or spray coating. Depending on the compositionof the size coat and when it is applied, the size coat may be cured inconjunction with the binder formulation 106 or cured separately. Asupersize coat including grinding aids may be applied over the size coatand cured with the binder formulation 106, cured with the size coat orcured separately.

Referring to FIG. 2, a structured abrasive article is shown and isgenerally designated 200. As illustrated, the structured abrasivearticle 200 may include a backing 202 and a plurality of shaped abrasivegrains 204 deposited thereon. In a particular aspect, the structuredabrasive article 200 may be manufactured using the process described inconjunction with FIG. 1.

In a particular aspect, the shaped abrasive grains 204 may be one ormore of the shaped abrasive grains described herein. Further, the shapedabrasive grains may include one or more, or any combination, of theshaped abrasive grains described herein. Further, one or more of theshaped abrasive grains described herein may include an uprightorientation probability. The upright orientation may be considered anorientation that corresponds to a favorable abrasive/cutting positionfor each shaped abrasive grain and the probability is a simplemathematical probability that the grain lands in the uprightorientation.

In a particular aspect, the upright orientation is at least fiftypercent (50%). In another aspect, the upright orientation is at leastfifty-five percent (55%). In another aspect, the upright orientation isat least sixty percent (60%). In another aspect, the upright orientationis at least sixty-five percent (65%). In another aspect, the uprightorientation is at least seventy percent (70%). In another aspect, theupright orientation is at least seventy-five percent (75%). In anotheraspect, the upright orientation is at least eighty percent (80%). Inanother aspect, the upright orientation is at least eighty-five percent(85%). In another aspect, the upright orientation is at least ninetypercent (90%). In another aspect, the upright orientation is at leastninety-five percent (95%). In another aspect, the upright orientation isone hundred percent (100%).

The body of each of the shaped abrasive grains described herein mayinclude a polycrystalline material. The polycrystalline material mayinclude abrasive grains. The abrasive grains may include nitrides,oxides, carbides, borides, oxynitrides, diamond, or a combinationthereof. Further, the abrasive grains may include an oxide selected fromthe group of oxides consisting of aluminum oxide, zirconium oxide,titanium oxide, yttrium oxide, chromium oxide, strontium oxide, siliconoxide, and a combination thereof.

In another aspect, the abrasive grains may include alumina. In yetanother aspect, the abrasive grains consist essentially of alumina.Further, the abrasive grains may have an average grain size of notgreater than about 500 microns. Alternatively, the average grain size isnot greater than about 250 microns. In another aspect, the average grainsize is not greater than about 100 microns. In another aspect, theaverage grain size is not greater than about 50 microns. In anotheraspect, the average grain size is not greater than about 30 microns. Inanother aspect, the average grain size is not greater than about 20microns. In another aspect, the average grain size is not greater thanabout 10 microns. In another aspect, the average grain size is notgreater than about 1 micron.

In another aspect, the average grain size is at least about 0.01microns. In another aspect, the average grain size is at least about0.05 microns. In another aspect, the average grain size is at leastabout 0.08 microns. In another aspect, the average grain size is atleast about 0.1 microns.

In another aspect, the body of each of the shaped abrasive grainsdescribed herein may be a composite that includes at least about 2different types of abrasive grains.

FIG. 3 and FIG. 4 illustrate a first embodiment of a shaped abrasivegrain 300. As shown in FIG. 3, the shaped abrasive grain 300 may includea body 301 that is generally prismatic with a first end face 302 and asecond end face 304. Further, the shaped abrasive grain 300 may includea first side face 310 extending between the first end face 302 and thesecond end face 304. A second side face 312 may extend between the firstend face 302 and the second end face 304 adjacent to the first side face310. As shown, the shaped abrasive grain 300 may also include a thirdside face 314 extending between the first end face 302 and the secondend face 304 adjacent to the second side face 312 and the first sideface 310.

As depicted in FIG. 3 and FIG. 4, the shaped abrasive grain 300 may alsoinclude a first edge 320 between the first side face 310 and the secondside face 312. The shaped abrasive grain 300 may also include a secondedge 322 between the second side face 312 and the third side face 314.Further, the shaped abrasive grain 300 may include a third edge 324between the third side face 314 and the first side face 312.

As shown, each end face 302, 304 the shaped abrasive grain 300 may begenerally triangular in shape. Each side face 310, 312, 314 may begenerally rectangular in shape. Further, the cross section of the shapedabrasive grain 300 in a plane parallel to the end faces 302, 304 isgenerally triangular. It can be appreciated that the shaped abrasivegrain 300 may include more than the three side faces 310, 312, 314 andthree edges 320, 322, 324. It may be further appreciated that dependingon the number of side faces 310, 312, 314, the end faces 302, 304 andcross section of the shaped abrasive grain 300 through a plane parallelto the end faces 302, 304 may have that shape of any polygon, e.g., aquadrilateral, a pentagon, a hexagon, a heptagon, an octagon, a nonagon,a decagon, etc. Further, the polygon may be convex, non-convex, concave,or non-concave.

FIG. 5 and FIG. 6 illustrate a second embodiment of a shaped abrasivegrain 500. As shown in FIG. 5, the shaped abrasive grain 500 may includea body 501 that is generally prismatic with a first end face 502 and asecond end face 504. Further, the shaped abrasive grain 500 may includea first side face 510 extending between the first end face 502 and thesecond end face 504. A second side face 512 may extend between the firstend face 502 and the second end face 504 adjacent to the first side face510. As shown, the shaped abrasive grain 500 may also include a thirdside face 514 extending between the first end face 502 and the secondend face 504 adjacent to the second side face 512 and the first sideface 510.

As depicted in FIG. 5 and FIG. 6, the shaped abrasive grain 500 may alsoinclude a first edge face 520 between the first side face 510 and thesecond side face 512. The shaped abrasive grain 500 may also include asecond edge face 522 between the second side face 512 and the third sideface 514. Further, the shaped abrasive grain 500 may include a thirdedge face 524 between the third side face 514 and the first side face512.

As shown, each end face 502, 504 the shaped abrasive grain 500 may begenerally triangular in shape. Each side face 510, 512, 514 may begenerally rectangular in shape. Further, the cross-section of the shapedabrasive grain 500 in a plane parallel to the end faces 502, 504 isgenerally triangular.

FIG. 7 and FIG. 8 illustrate a third embodiment of a shaped abrasivegrain 700. As shown in FIG. 7, the shaped abrasive grain 700 may includea body 701 that is generally prismatic with a first end face 702 and asecond end face 704. Further, the shaped abrasive grain 700 may includea first side face 710 extending between the first end face 702 and thesecond end face 704. A second side face 712 may extend between the firstend face 702 and the second end face 704 adjacent to the first side face710. As shown, the shaped abrasive grain 700 may also include a thirdside face 714 extending between the first end face 702 and the secondend face 704 adjacent to the second side face 712 and the first sideface 710.

As depicted in FIG. 7 and FIG. 8, the shaped abrasive grain 700 may alsoinclude a first concave edge channel 720 between the first side face 710and the second side face 712. The shaped abrasive grain 700 may alsoinclude a second concave edge channel 722 between the second side face712 and the third side face 714. Further, the shaped abrasive grain 700may include a third concave edge channel 724 between the third side face714 and the first side face 712.

As shown, each end face 702, 704 the shaped abrasive grain 700 may begenerally triangular in shape. Each side face 710, 712, 714 may begenerally rectangular in shape. Further, the cross-section of the shapedabrasive grain 700 in a plane parallel to the end faces 702, 704 isgenerally triangular.

FIG. 9 and FIG. 10 illustrate a fourth embodiment of a shaped abrasivegrain 900. As shown in FIG. 9, the shaped abrasive grain 900 may includea body 901 that is generally prismatic with a first end face 902 and asecond end face 904. Further, the shaped abrasive grain 900 may includea first side face 910 extending between the first end face 902 and thesecond end face 904. A second side face 912 may extend between the firstend face 902 and the second end face 904 adjacent to the first side face910. As shown, the shaped abrasive grain 900 may also include a thirdside face 914 extending between the first end face 902 and the secondend face 904 adjacent to the second side face 912 and the first sideface 910.

As depicted in FIG. 9 and FIG. 10, the shaped abrasive grain 900 mayalso include a first V shaped edge channel face 920 between the firstside face 910 and the second side face 912. The shaped abrasive grain900 may also include a second V shaped edge channel face 922 between thesecond side face 912 and the third side face 914. Further, the shapedabrasive grain 900 may include a third V shaped edge channel face 924between the third side face 914 and the first side face 912.

As shown, each end face 902, 904 the shaped abrasive grain 900 may begenerally triangular in shape. Each side face 910, 912, 914 may begenerally rectangular in shape. Further, the cross-section of the shapedabrasive grain 900 in a plane parallel to the end faces 902, 904 isgenerally triangular.

In the exemplary embodiments shown in FIG. 3 through FIG. 10, it can beappreciated that the edges 320, 322, 324; the edge faces 520, 522, 524;the concave edge channels 720, 722, 724; and the V shaped edge channels920, 922, 924 may be considered edge structures. Further, the edgestructures ensure that when the shaped abrasive grains 300, 500, 700,900 are deposited, or otherwise disposed, on a backing, a side face willland on the backing and an edge structure will face up, or outward, fromthe backing. Further, the edge structures provide sharp edges thatprovide substantially increased grinding performance.

Additionally, it may be appreciated that in each of the exemplaryembodiments shown in FIG. 3 through FIG. 10, the face of the shapedabrasive grain 300, 500, 700, 900, i.e., the base, that is touching abacking has an area that is substantially greater than the area of theportion of the shaped abrasive grain 300, 500, 700, 900 that is pointedoutward, or upward, e.g., the edge structure.

In particular, the base may comprise at least about thirty percent (30%)of the total surface area of the particle. In another aspect, the basemay comprise at least about forty percent (40%) of the total surfacearea of the particle. In another aspect, the base may comprise at leastabout fifty percent (50%) of the total surface area of the particle. Inanother aspect, the base may comprise at least about sixty percent (60%)of the total surface area of the particle. In another aspect, the basemay comprise no greater than ninety-nine percent (99%) of the totalsurface area of the particle. In another aspect, the base may compriseno greater than ninety-five percent (95%) of the total surface area ofthe particle. In another aspect, the base may comprise no greater thanninety percent (90%) of the total surface area of the particle. Inanother aspect, the base may comprise no greater than eighty percent(80%) of the total surface area of the particle. In another aspect, thebase may comprise no greater than seventy-five percent (75%) of thetotal surface area of the particle.

Referring to FIG. 11 and FIG. 12, a fifth embodiment of a shapedabrasive grain is shown and is generally designated 1100. As shown, theshaped abrasive grain 1100 may include a body 1101 that is generallypyramid shaped with a generally triangle shaped bottom face 1102.Further, the shaped abrasive grain 1100 may be formed with a hole 1104,i.e., an opening, therein.

In a particular aspect, the hole 1104 may define a central axis 1106that passes through a center of the hole 1104. Further, the shapedabrasive grain 1100 may also define a central axis 1108 that passesthrough a center of the shaped abrasive grain 1100. It may beappreciated that the hole 1104 may be formed in the shaped abrasivegrain 1100 such that the central axis 1106 of the hole 1104 is spaced adistance 1110 above the central axis 1108 of the shaped abrasive grain1100. As such, a center of mass of the shaped abrasive grain 1100 may bemoved below the geometric midpoint of the shaped abrasive grain 1100.Moving the center of mass below the geometric midpoint of the shapedabrasive grain may ensure that the shaped abrasive grain 1100 lands onthe same face, e.g., the bottom face 1102, when dropped, or otherwisedeposited, onto a backing, such that the shaped abrasive grain has anupright orientation.

In a particular embodiment, the center of mass of is displaced from thegeometric midpoint by a distance that is equal to 0.05 the height (h)along a vertical axis of the body 1102 defining a height. In anotheraspect, the center of mass may be displaced by a distance of at leastabout 0.1(h). In another aspect, the center of mass may be displaced bya distance of at least about 0.15(h). In another aspect, the center ofmass may be displaced by a distance of at least about 0.18(h). Inanother aspect, the center of mass may be displaced by a distance of atleast about 0.2(h). In another aspect, the center of mass may bedisplaced by a distance of at least about 0.22(h). In another aspect,the center of mass may be displaced by a distance of at least about0.25(h). In another aspect, the center of mass may be displaced by adistance of at least about 0.27(h). In another aspect, the center ofmass may be displaced by a distance of at least about 0.3(h). In anotheraspect, the center of mass may be displaced by a distance of at leastabout 0.32(h). In another aspect, the center of mass may be displaced bya distance of at least about 0.35(h). In another aspect, the center ofmass may be displaced by a distance of at least about 0.38(h).

In another aspect, the center of mass is displaced a distance no greaterthan 0.5(h). In yet another aspect, the center of mass is displaced adistance no greater than 0.49 (h). In still another aspect, the centerof mass is displaced a distance no greater than 0.48(h). In anotheraspect, the center of mass is displaced a distance no greater than0.45(h). In still another aspect, the center of mass is displaced adistance no greater than 0.43(h). In yet still another aspect, thecenter of mass is displaced a distance no greater than 0.40(h). Inanother aspect, the center of mass is displaced a distance no greaterthan 0.39(h). In another aspect, the center of mass is displaced adistance no greater than 0.38(h).

Further, the center of mass may be displaced so that the center of massis closer to a base, e.g., the bottom face 1102, of the body 1101, thana top of the body 1101 when the shaped abrasive grain 1100 is in anupright orientation as shown in FIG. 11.

In another embodiment, the center of mass may be displaced from thegeometric midpoint by a distance 1110 that is equal to 0.05 the width(w) along a horizontal axis of the of the body 1102 defining the width.In another aspect, the center of mass may be displaced by a distance ofat least about 0.1(w). In another aspect, the center of mass may bedisplaced by a distance of at least about 0.15(w). In another aspect,the center of mass may be displaced by a distance of at least about0.18(w). In another aspect, the center of mass may be displaced by adistance of at least about 0.2(w). In another aspect, the center of massmay be displaced by a distance of at least about 0.22(w). In anotheraspect, the center of mass may be displaced by a distance of at leastabout 0.25(w). In another aspect, the center of mass may be displaced bya distance of at least about 0.27(w). In another aspect, the center ofmass may be displaced by a distance of at least about 0.3(w). In anotheraspect, the center of mass may be displaced by a distance of at leastabout 0.32(w). In another aspect, the center of mass may be displaced bya distance of at least about 0.35(w). In another aspect, the center ofmass may be displaced by a distance of at least about 0.38(w).

In another aspect, the center of mass is displaced a distance no greaterthan 0.5(w). In yet another aspect, the center of mass is displaced adistance no greater than 0.49 (w). In still another aspect, the centerof mass is displaced a distance no greater than 0.48(w). In anotheraspect, the center of mass is displaced a distance no greater than0.45(w). In still another aspect, the center of mass is displaced adistance no greater than 0.43(w). In yet still another aspect, thecenter of mass is displaced a distance no greater than 0.40(w). Inanother aspect, the center of mass is displaced a distance no greaterthan 0.39(w). In another aspect, the center of mass is displaced adistance no greater than 0.38(w).

In another embodiment, the center of mass may be displaced from thegeometric midpoint by a distance that is equal to 0.05 the length (l)along a longitudinal axis of the body 1102 defining a length. In anotheraspect, the center of mass may be displaced by a distance of at leastabout 0.1(l). In another aspect, the center of mass may be displaced bya distance of at least about 0.15(l). In another aspect, the center ofmass may be displaced by a distance of at least about 0.18(l). Inanother aspect, the center of mass may be displaced by a distance of atleast about 0.2(l). In another aspect, the center of mass may bedisplaced by a distance of at least about 0.22(l). In another aspect,the center of mass may be displaced by a distance of at least about0.25(l). In another aspect, the center of mass may be displaced by adistance of at least about 0.27(l). In another aspect, the center ofmass may be displaced by a distance of at least about 0.3(l). In anotheraspect, the center of mass may be displaced by a distance of at leastabout 0.32(l). In another aspect, the center of mass may be displaced bya distance of at least about 0.35(l). In another aspect, the center ofmass may be displaced by a distance of at least about 0.38(l).

In another aspect, the center of mass is displaced a distance no greaterthan 0.5(l). In yet another aspect, the center of mass is displaced adistance no greater than 0.49 (l). In still another aspect, the centerof mass is displaced a distance no greater than 0.48(l). In anotheraspect, the center of mass is displaced a distance no greater than0.45(l). In still another aspect, the center of mass is displaced adistance no greater than 0.43(l). In yet still another aspect, thecenter of mass is displaced a distance no greater than 0.40(l). Inanother aspect, the center of mass is displaced a distance no greaterthan 0.39(l). In another aspect, the center of mass is displaced adistance no greater than 0.38(l).

FIG. 13 and FIG. 14 illustrate a sixth embodiment of a shaped abrasivegrain that is generally designated 1300. As depicted, the shapedabrasive grain 1300 may include a body 1301 that may include a centralportion 1302 that extends along a longitudinal axis 1304. A first radialarm 1306 may extend outwardly from the central portion 1302 along thelength of the central portion 1302. A second radial arm 1308 may extendoutwardly from the central portion 1302 along the length of the centralportion 1302. A third radial arm 1310 may extend outwardly from thecentral portion 1302 along the length of the central portion 1302.Moreover, a fourth radial arm 1312 may extend outwardly from the centralportion 1302 along the length of the central portion 1302. The radialarms 1306, 1308, 1310, 1312 may be equally spaced around the centralportion 1302 of the shaped abrasive grain 1300.

As shown in FIG. 13, the first radial arm 1306 may include a generallyarrow shaped distal end 1320. The second radial arm 1308 may include agenerally arrow shaped distal end 1322. The third radial arm 1310 mayinclude a generally arrow shaped distal end 1324. Further, the fourthradial arm 1312 may include a generally arrow shaped distal end 1326.

FIG. 13 also indicates that the shaped abrasive grain 1300 may be formedwith a first void 1330 between the first radial arm 1306 and the secondradial arm 1308. A second void 1332 may be formed between the secondradial arm 1308 and the third radial arm 1310. A third void 1334 mayalso be formed between the third radial arm 1310 and the fourth radialarm 1312. Additionally, a fourth void 1336 may be formed between thefourth radial arm 1312 and the first radial arm 1306.

As shown in FIG. 13, the shaped abrasive grain 1300 may include a length1340, a height 1342, and a width 1344. In a particular aspect, thelength 1340 is greater than the height 1342 and the height 1342 isgreater than the width 1344. In a particular aspect, the shaped abrasivegrain 1300 may define a primary aspect ratio that is the ratio of thelength 1340 to the height 1342 (length:height). Further, the shapedabrasive grain 1300 may define a secondary aspect ratio that is theratio of the height 1342 to the width 1344 (height:width). Finally, theshaped abrasive grain 1300 may define a tertiary aspect ratio that isthe ratio of the length 1340 to the width 1342 (length:width).

In a particular aspect, the primary aspect ratio is at least 1:1. Inanother aspect, the primary aspect ratio is at least 2:1. In anotheraspect, the primary aspect ratio is at least 2.5:1. In another aspect,the primary aspect ratio is at least 3:1. In another aspect, the primaryaspect ratio is at least 3.5:1. In another aspect, the primary aspectratio is at least 4:1. In another aspect, the primary aspect ratio is atleast 4.5:1. In another aspect, the primary aspect ratio is at least5:1. In another aspect, the primary aspect ratio is at least 5.5:1. Inanother aspect, the primary aspect ratio is at least 6:1. In anotheraspect, the primary aspect ratio is at least 6.5:1. In another aspect,the primary aspect ratio is at least 7:1. In another aspect, the primaryaspect ratio is at least 7.5:1. In another aspect, the primary aspectratio is at least 8:1. In another aspect, the primary aspect ratio is atleast 8.5:1. In another aspect, the primary aspect ratio is at least9:1. In another aspect, the primary aspect ratio is at least 9.5:1. Inanother aspect, the primary aspect ratio is at least 10:1.

In a particular aspect, the secondary aspect ratio is at least 1:1. Inanother aspect, the secondary aspect ratio is at least 1.5:1. In anotheraspect, the secondary aspect ratio is 2:1. In another aspect, thesecondary aspect ratio is at least 2.5:1. In another aspect, thesecondary aspect ratio is at least 3:1. In another aspect, the secondaryaspect ratio is at least 3.5:1. In another aspect, the secondary aspectratio is at least 4:1. In another aspect, the secondary aspect ratio isat least 4.5:1. In another aspect, the secondary aspect ratio is atleast 5:1. In another aspect, the secondary aspect ratio is at least5.5:1. In another aspect, the secondary aspect ratio is at least 6:1. Inanother aspect, the secondary aspect ratio is at least 6.5:1. In anotheraspect, the secondary aspect ratio is at least 7:1. In another aspect,the secondary aspect ratio is at least 7.5:1. In another aspect, thesecondary aspect ratio is at least 8:1. In another aspect, the secondaryaspect ratio is at least 8.5:1. In another aspect, the secondary aspectratio is at least 9:1. In another aspect, the secondary aspect ratio isat least 9.5:1. In another aspect, the secondary aspect ratio is atleast 10:1.

In a particular aspect, the tertiary aspect ratio is at least 1:1. Inanother aspect, the tertiary aspect ratio is at least 1.5:1. In anotheraspect, the tertiary aspect ratio is 2:1. In another aspect, thetertiary aspect ratio is at least 2.5:1. In another aspect, the tertiaryaspect ratio is at least 3:1. In another aspect, the tertiary aspectratio is at least 3.5:1. In another aspect, the tertiary aspect ratio isat least 4:1. In another aspect, the tertiary aspect ratio is at least4.5:1. In another aspect, the tertiary aspect ratio is at least 5:1. Inanother aspect, the tertiary aspect ratio is at least 5.5:1. In anotheraspect, the tertiary aspect ratio is at least 6:1. In another aspect,the tertiary aspect ratio is at least 6.5:1. In another aspect, thetertiary aspect ratio is at least 7:1. In another aspect, the tertiaryaspect ratio is at least 7.5:1. In another aspect, the tertiary aspectratio is at least 8:1. In another aspect, the tertiary aspect ratio isat least 8.5:1. In another aspect, the tertiary aspect ratio is at least9:1. In another aspect, the tertiary aspect ratio is at least 9.5:1. Inanother aspect, the tertiary aspect ratio is at least 10:1.

In a particular aspect, the shape of the shaped abrasive grain 1300 withrespect to the primary aspect ratio is generally rectangular, e.g., flator curved. Moreover, the shape of the shaped abrasive grain 1300 withrespect to the secondary aspect ratio may be any polyhedral shape, e.g.,a triangle, a square, a rectangle, a pentagon, etc. The shape of theshaped abrasive grain 1300 with respect to the secondary aspect ratiomay also be the shape of any alphanumeric character, e.g., 1, 2, 3,etc., A, B, C. etc. Further, the shape of the shaped abrasive grain 1300with respect to the secondary aspect ratio may be a character selectedfrom the Greek alphabet, the modern Latin alphabet, the ancient Latinalphabet, the Russian alphabet, any other alphabet, or any combinationthereof. Further, the shape of the shaped abrasive grain 1300 withrespect to the secondary aspect ratio may be a Kanji character.

In another aspect of the shaped abrasive grain 1300, the width 1344 isgreater than the height 1342 and the height 1342 is greater than thelength 1340. In this aspect, the shaped abrasive grain 1300 may define aprimary aspect ratio that is the ratio of the width 1344 to the height1342 (width:height). Further, the shaped abrasive grain 1300 may definea secondary aspect ratio that is the ratio of the height 1342 to thelength 1340 (height:length). Finally, the shaped abrasive grain 1300 maydefine a tertiary aspect ratio that is the ratio of the width 1342 tothe length 1340 (width:length).

In a particular aspect, the primary aspect ratio is at least 2:1. Inanother aspect, the primary aspect ratio is at least 2.5:1. In anotheraspect, the primary aspect ratio is at least 3:1. In another aspect, theprimary aspect ratio is at least 3.5:1. In another aspect, the primaryaspect ratio is at least 4:1. In another aspect, the primary aspectratio is at least 4.5:1. In another aspect, the primary aspect ratio isat least 5:1. In another aspect, the primary aspect ratio is at least5.5:1. In another aspect, the primary aspect ratio is at least 6:1. Inanother aspect, the primary aspect ratio is at least 6.5:1. In anotheraspect, the primary aspect ratio is at least 7:1. In another aspect, theprimary aspect ratio is at least 7.5:1. In another aspect, the primaryaspect ratio is at least 8:1. In another aspect, the primary aspectratio is at least 8.5:1. In another aspect, the primary aspect ratio isat least 9:1. In another aspect, the primary aspect ratio is at least9.5:1. In another aspect, the primary aspect ratio is at least 10:1.

In a particular aspect, the secondary aspect ratio is at least 1.5:1. Inanother aspect, the secondary aspect ratio is 2:1. In another aspect,the secondary aspect ratio is at least 2.5:1. In another aspect, thesecondary aspect ratio is at least 3:1. In another aspect, the secondaryaspect ratio is at least 3.5:1. In another aspect, the secondary aspectratio is at least 4:1. In another aspect, the secondary aspect ratio isat least 4.5:1. In another aspect, the secondary aspect ratio is atleast 5:1. In another aspect, the secondary aspect ratio is at least5.5:1. In another aspect, the secondary aspect ratio is at least 6:1. Inanother aspect, the secondary aspect ratio is at least 6.5:1. In anotheraspect, the secondary aspect ratio is at least 7:1. In another aspect,the secondary aspect ratio is at least 7.5:1. In another aspect, thesecondary aspect ratio is at least 8:1. In another aspect, the secondaryaspect ratio is at least 8.5:1. In another aspect, the secondary aspectratio is at least 9:1. In another aspect, the secondary aspect ratio isat least 9.5:1. In another aspect, the secondary aspect ratio is atleast 10:1.

In a particular aspect, the tertiary aspect ratio is at least 1.5:1. Inanother aspect, the tertiary aspect ratio is 2:1. In another aspect, thetertiary aspect ratio is at least 2.5:1. In another aspect, the tertiaryaspect ratio is at least 3:1. In another aspect, the tertiary aspectratio is at least 3.5:1. In another aspect, the tertiary aspect ratio isat least 4:1. In another aspect, the tertiary aspect ratio is at least4.5:1. In another aspect, the tertiary aspect ratio is at least 5:1. Inanother aspect, the tertiary aspect ratio is at least 5.5:1. In anotheraspect, the tertiary aspect ratio is at least 6:1. In another aspect,the tertiary aspect ratio is at least 6.5:1. In another aspect, thetertiary aspect ratio is at least 7:1. In another aspect, the tertiaryaspect ratio is at least 7.5:1. In another aspect, the tertiary aspectratio is at least 8:1. In another aspect, the tertiary aspect ratio isat least 8.5:1. In another aspect, the tertiary aspect ratio is at least9:1. In another aspect, the tertiary aspect ratio is at least 9.5:1. Inanother aspect, the tertiary aspect ratio is at least 10:1.

In a particular aspect, the shape of the shaped abrasive grain 1300 withrespect to the secondary aspect ratio is generally rectangular, e.g.,flat or curved. Moreover, the shape of the shaped abrasive grain 1300with respect to the primary aspect ratio may be any polyhedral shape,e.g., a triangle, a square, a rectangle, a pentagon, etc. The shape ofthe shaped abrasive grain 1300 with respect to the primary aspect ratiomay also be the shape of any alphanumeric character, e.g., 1, 2, 3,etc., A, B, C. etc. Further, the shape of the shaped abrasive grain 1300with respect to the primary aspect ratio may be a character selectedfrom the Greek alphabet, the modern Latin alphabet, the ancient Latinalphabet, the Russian alphabet, any other alphabet, or any combinationthereof. Moreover, the shape of the shaped abrasive grain 1300 withrespect to the primary aspect ratio may be a Kanji character.

Referring now to FIG. 15 and FIG. 16, a seventh embodiment of a shapedabrasive grain is shown and is generally designated 1500. As shown, theshaped abrasive grain 1500 may include a body 1501 that includes a flatbottom 1502 and a generally dome shaped top 1504. The domed shaped top1504 may be formed with a first edge 1506, a second edge 1508, a thirdedge 1510, a fourth edge 1512, and a fifth edge 1514. It may beappreciated that the shaped abrasive grain 1500 may include more or lessthan five edges 1506, 1508, 1510, 1512, 1514. Further, the edges 1506,1508, 1510, 1512, 1514 may be equally spaced radially around a center ofthe dome shaped top 1504.

In a particular aspect, the edges 1506, 1508, 1510, 1512, 1514 in thedome shaped top 1504 may be formed by injecting the material comprisingthe shaped abrasive grain 1500 through a generally star shaped nozzle.It may be appreciated that the shape of the shaped abrasive grain 1500may facilitate orientation of the shaped abrasive grain 1500 as it isdropped, or otherwise deposited, on a backing. Specifically, the domeshaped top 1504 will allow the shaped abrasive grain 1500 to roll ontothe flat bottom 1502 ensuring that the edges face out, or up, from thebacking.

FIG. 17 and FIG. 18 illustrate an eighth embodiment of a shaped abrasivegrain, designated 1700. As depicted, the shaped abrasive grain 1700 mayinclude a body 1701 that includes a flat bottom 1702 and a generallydome shaped top 1704. The domed shaped top 1704 may be formed with apeak 1706. In a particular aspect, the peak 1706 in the dome shaped top1704 may be formed by injecting the material comprising the shapedabrasive grain 1700 through a generally round, generally small nozzle.It may be appreciated that the shape of the shaped abrasive grain 1700may facilitate orientation of the shaped abrasive grain 1700 as it isdropped, or otherwise deposited, on a backing. Specifically, the domeshaped top 1704 and the peak 1706 will allow the shaped abrasive grain1700 to roll onto the flat bottom 1702 ensuring that the peak 1706 andthe dome shaped top 1704 face out, or up, from the backing.

Referring now to FIG. 19 and FIG. 20, a ninth embodiment of a shapedabrasive grain is shown and is generally designated 1900. As shown, theshaped abrasive grain 1900 may include a body 1901 that is generally boxshaped with six exterior faces 1902 and twelve 1904 edges. Further, theshaped abrasive grain 1900 may be formed with a generally X shaped hole1906, i.e., an opening, through the shaped abrasive grain 1900 parallelto a longitudinal axis 1908 that passes through a center 1910 of theshaped abrasive grain. Further, a center 1912 of the X shaped hole 1906may be spaced a distance 1914 from the longitudinal axis 1908. As such,a center of mass 1916 of the shaped abrasive grain 1900 may be movedbelow the geometric midpoint 1910 of the shaped abrasive grain 1900.Moving the center of mass below the geometric midpoint of the shapedabrasive grain may ensure that the shaped abrasive grain 1900 lands onthe same face when dropped, or otherwise deposited, onto a backing.

It may be appreciated that the X shaped hole 1906 may be formed alongthe longitudinal axis 1908 through the geometric midpoint 1910 of theshaped abrasive grain 1900. Further, it may be appreciated that the Xshaped hole 1906 may be rotated forty-five degrees (45°) and in such acase the hole 1906 would appear to be generally +shaped. It may beappreciated that the hole 1906 formed in the shaped abrasive grain 1900may have any shape: polygonal or otherwise.

FIG. 21 through FIG. 23 depict a tenth embodiment of a shaped abrasivegrain that is generally designated 2100. As shown, the shaped abrasivegrain 2100 may include a body 2101 that may have a first end face 2102and a second end face 2104. In a particular aspect, depending on theorientation, the first end face 2102 may be a base surface and thesecond end face 2104 may be an upper surface. Further, the shapedabrasive grain 2100 may include a first lateral face 2106 extendingbetween the first end face 2102 and the second end face 2104. A secondlateral face 2108 may extend between the first end face 2102 and thesecond end face 2104. Further, a third lateral face 2110 may extendbetween the first end face 2102 and the second end face 2104. A fourthlateral face 2112 may also extend between the first end face 2102 andthe second end face 2104.

As shown, the first end face 2102 and the second end face 2104 areparallel to each other. However, in a particular aspect, the first endface 2102 is rotated with respect to the second end face 2104 toestablish a twist angle 2114. In a particular aspect, the twist angle2114 is at least about one degree. In another aspect, the twist angle2114 is at least about two degrees. In another aspect, the twist angle2114 is at least about five degrees. In another aspect, the twist angle2114 is at least about eight degrees. In another aspect, the twist angle2114 is at least about ten degrees. In another aspect, the twist angle2114 is at least about twelve degrees. In another aspect, the twistangle 2114 is at least about fifteen degrees. In another aspect, thetwist angle 2114 is at least about eighteen degrees. In another aspect,the twist angle 2114 is at least about twenty degrees. In anotheraspect, the twist angle 2114 is at least about twenty-five degrees. Inanother aspect, the twist angle 2114 is at least about thirty degrees.In another aspect, the twist angle 2114 is at least about forty degrees.In another aspect, the twist angle 2114 is at least about fifty degrees.In another aspect, the twist angle 2114 is at least about sixty degrees.In another aspect, the twist angle 2114 is at least about seventydegrees. In another aspect, the twist angle 2114 is at least abouteighty degrees. In another aspect, the twist angle 2114 is at leastabout ninety degrees.

It can be appreciated that the twist angle 2100 of the shaped abrasivegrain may be a horizontal twist angle, i.e., along a longitudinal axisof the body 2101 defining a length. In another aspect, the twist angle2100 of the shaped abrasive grain may be a vertical twist angle, i.e.,along a vertical axis defining a height of the body 2101.

Referring to FIG. 24 and FIG. 25, an eleventh embodiment of a shapedabrasive grain is shown and is generally designated 2400. Asillustrated, the shaped abrasive grain 2400 may include a body 2401 thatmay include a central portion 2402 that extends along a longitudinalaxis 2404. A first radial arm 2406 may extend outwardly from the centralportion 2402 along the length of the central portion 2402. A secondradial arm 2408 may extend outwardly from the central portion 2402 alongthe length of the central portion 2402. A third radial arm 2410 mayextend outwardly from the central portion 2402 along the length of thecentral portion 2402. Moreover, a fourth radial arm 2412 may extendoutwardly from the central portion 2402 along the length of the centralportion 2402. The radial arms 2406, 2408, 2410, 2412 may be equallyspaced around the central portion 2402 of the shaped abrasive grain2400.

As shown in FIG. 24, the first radial arm 2406 may include a generallybox shaped distal end 2420. The second radial arm 2408 may include agenerally box shaped distal end 2422. The third radial arm 2410 mayinclude a generally box shaped distal end 2424. Further, the fourthradial arm 2412 may include a generally box shaped distal end 2426.

FIG. 24 and FIG. 25 further show that the shaped abrasive grain 2400 maybe formed with a hole 2428 through the shaped abrasive grain 2400 alongthe longitudinal axis 2404. As shown, the hole 2428 may be generallytriangular in shape. It may be appreciated that in other aspects thehole 2428 formed in the shaped abrasive grain 2400 may have any shape:polygonal or otherwise.

FIG. 26 and FIG. 27 illustrate a twelfth embodiment of a shaped abrasivegrain that is generally designated 2600. As shown, the shaped abrasivegrain 2600 may include a body 2601 that may include a central portion2602 that extends along a longitudinal axis 2604. A first radial arm2606 may extend outwardly from the central portion 2602 along the lengthof the central portion 2602. A second radial arm 2608 may extendoutwardly from the central portion 2602 along the length of the centralportion 2602. A third radial arm 2610 may extend outwardly from thecentral portion 2602 along the length of the central portion 2602.Moreover, a fourth radial arm 2612 may extend outwardly from the centralportion 2602 along the length of the central portion 2602. The radialarms 2606, 2608, 2610, 2612 may be equally spaced around the centralportion 2602 of the shaped abrasive grain 2600.

As shown in FIG. 26 and FIG. 27, the first radial arm 2606 may include agenerally box shaped distal end 2620 formed with a V shaped channel2622. The second radial arm 2608 may include a generally box shapeddistal end 2624 formed with a V shaped channel 2626. The third radialarm 2610 may also include a generally box shaped distal end 2628 formedwith a V shaped channel 2630. Further, the fourth radial arm 2612 mayinclude a generally box shaped distal end 2632 that is also formed witha V shape channel 2634.

FIG. 28 and FIG. 29 illustrate a thirteenth embodiment of a shapedabrasive grain that is generally designated 2800. As shown, the shapedabrasive grain 2800 may include a body 2801 that may include a centralportion 2802 that extends along a longitudinal axis 2804. A first radialarm 2806 may extend outwardly from the central portion 2802 along thelength of the central portion 2802. A second radial arm 2808 may extendoutwardly from the central portion 2802 along the length of the centralportion 2802. A third radial arm 2810 may extend outwardly from thecentral portion 2802 along the length of the central portion 2802.Moreover, a fourth radial arm 2812 may extend outwardly from the centralportion 2802 along the length of the central portion 2802. The radialarms 2806, 2808, 2810, 2812 may be equally spaced around the centralportion 2802 of the shaped abrasive grain 2800.

As shown in FIG. 28 and FIG. 29, the first radial arm 2806 may include agenerally box shaped distal end 2820 formed with a concave channel 2822.The second radial arm 2808 may include a generally box shaped distal end2824 formed with a concave channel 2826. The third radial arm 2810 mayalso include a generally box shaped distal end 2828 formed with aconcave channel 2830. Further, the fourth radial arm 2812 may include agenerally box shaped distal end 2832 that is also formed with a concavechannel 2834.

FIG. 30 and FIG. 31 illustrate a fourteenth embodiment of a shapedabrasive grain that is generally designated 3000. As depicted, theshaped abrasive grain 3000 may include a body 3001 having a centralportion 3002 that extends along a longitudinal axis 3004. A first radialarm 3006 may extend outwardly from the central portion 3002 along thelength of the central portion 3002. A second radial arm 3008 may extendoutwardly from the central portion 3002 along the length of the centralportion 3002. A third radial arm 3010 may extend outwardly from thecentral portion 3002 along the length of the central portion 3002.Moreover, a fourth radial arm 3012 may extend outwardly from the centralportion 3002 along the length of the central portion 3002. The radialarms 3006, 3008, 3010, 3012 may be equally spaced around the centralportion 3002 of the shaped abrasive grain 3000.

As shown in FIG. 30, the first radial arm 3006 may include a generally Tshaped distal end 3020. The second radial arm 3008 may include agenerally T shaped distal end 3022. The third radial arm 3010 mayinclude a generally T shaped distal end 3024. Further, the fourth radialarm 3012 may include a generally T shaped distal end 3026.

FIG. 30 also indicates that the shaped abrasive grain 3000 may be formedwith a first void 3030 between the first radial arm 3006 and the secondradial arm 3008. A second void 3032 may be formed between the secondradial arm 3008 and the third radial arm 3010. A third void 3034 mayalso be formed between the third radial arm 3010 and the fourth radialarm 3012. Additionally, a fourth void 3036 may be formed between thefourth radial arm 3012 and the first radial arm 3006.

FIG. 32 and FIG. 33 illustrate a fifteenth embodiment of a shapedabrasive grain that is generally designated 3200. As depicted, theshaped abrasive grain 3200 may include a body 3201 that may include acentral portion 3202 that extends along a longitudinal axis 3204. Afirst radial arm 3206 may extend outwardly from the central portion 3202along the length of the central portion 3202. A second radial arm 3208may extend outwardly from the central portion 3202 along the length ofthe central portion 3202. A third radial arm 3210 may extend outwardlyfrom the central portion 3202 along the length of the central portion3202. Moreover, a fourth radial arm 3212 may extend outwardly from thecentral portion 3202 along the length of the central portion 3202. Theradial arms 3206, 3208, 3210, 3212 may be equally spaced around thecentral portion 3202 of the shaped abrasive grain 3200.

As shown in FIG. 32, the first radial arm 3206 may include a generallyrounded T shaped distal end 3220. The second radial arm 3208 may includea generally rounded T shaped distal end 3222. The third radial arm 3210may include a generally rounded T shaped distal end 3224. Further, thefourth radial arm 3212 may include a generally rounded T shaped distalend 3226.

FIG. 32 also indicates that the shaped abrasive grain 3200 may be formedwith a first void 3230 between the first radial arm 3206 and the secondradial arm 3208. A second void 3232 may be formed between the secondradial arm 3208 and the third radial arm 3210. A third void 3234 mayalso be formed between the third radial arm 3210 and the fourth radialarm 3212. Additionally, a fourth void 3236 may be formed between thefourth radial arm 3212 and the first radial arm 3206.

FIG. 34 and FIG. 35 illustrate a sixteenth embodiment of a shapedabrasive grain that is generally designated 3400. As depicted, theshaped abrasive grain 3400 may include a body 3401 having a centralportion 3402 that extends along a longitudinal axis 3404. The centralportion 3402 may be formed with a hole 3406 along the longitudinal axis3404 along the entire length of the central portion 3402 of the shapedabrasive grain 3400.

A generally triangular first radial arm 3410 may extend outwardly fromthe central portion 3402 of the shaped abrasive grain 3400 along thelength of the central portion 3402. A generally triangular second radialarm 3412 may extend outwardly from the central portion 3402 of theshaped abrasive grain 3400 along the length of the central portion 3402.A generally triangular third radial arm 3414 may extend outwardly fromthe central portion 3402 of the shaped abrasive grain 3400 along thelength of the central portion 3402. A generally triangular fourth radialarm 3416 may extend outwardly from the central portion 3402 of theshaped abrasive grain 3400 along the length of the central portion 3402.Further, a generally triangular fifth radial arm 3418 may extendoutwardly from the central portion 3402 of the shaped abrasive grain3400 along the length of the central portion 3402.

As further depicted in FIG. 34 and FIG. 35, a generally triangular sixthradial arm 3420 may extend outwardly from the central portion 3402 ofthe shaped abrasive grain 3400 along the length of the central portion3402. A generally triangular seventh radial arm 3422 may extendoutwardly from the central portion 3402 of the shaped abrasive grain3400 along the length of the central portion 3402. A generallytriangular eighth radial arm 3424 may extend outwardly from the centralportion 3402 of the shaped abrasive grain 3400 along the length of thecentral portion 3402. A generally triangular ninth radial arm 3426 mayextend outwardly from the central portion 3402 of the shaped abrasivegrain 3400 along the length of the central portion 3402. Moreover, agenerally triangular tenth radial arm 3428 may extend outwardly from thecentral portion 3402 of the shaped abrasive grain 3400 along the lengthof the central portion 3402.

In a particular aspect, the radial arms 3410, 3412, 3414, 3416, 3418,3420, 3422, 3424, 3426, 3428 may be equally spaced around the centralportion 3402 of the shaped abrasive grain to form a generally starshaped first end face 3430, a generally star shaped second end face 3432and a generally star shaped cross section taken parallel to the endfaces 3430, 3432.

Referring now to FIG. 36 and FIG. 37, a seventeenth embodiment of ashaped abrasive grain is shown and is generally designated 3600. Asshown, the shaped abrasive grain 3600 may include a body 3601 having afirst end face 3602 and a second end face 3604. In a particular aspect,depending on the orientation, the first end face 3602 may be a basesurface and the second end face 3604 may be an upper surface. Further,the shaped abrasive grain 3600 may be formed with a hole 3606 along alongitudinal axis 3608. As shown, the hole 3606 may be generally boxshaped.

FIG. 36 and FIG. 37 show that the shaped abrasive grain 3600 may includea generally K shaped first side face 3610 extending between the firstend face 3602 and the second end face 3604. The shaped abrasive grain3600 may also include a generally K shaped second side face 3612extending between the first end face 3602 and the second end face 3604opposite the generally K shaped first side face 3610.

As illustrated, the shaped abrasive grain 3600 may include a generallyflat third side face 3614 extending between the first K shaped side face3610 and the second K shaped side face 3612 and between the first endface 3602 and the second end face 3604. The shaped abrasive grain 3600may also include a generally flat fourth side face 3616 extendingbetween the first K shaped side face 3610 and the second K shape sideface 3612 opposite the generally flat third side face 3614.

FIG. 38 and FIG. 39 depict an eighteenth embodiment of a shaped abrasivegrain that is generally designated 3800. As shown, the shaped abrasivegrain 3800 may include a body 3801 having a first end face 3802 and asecond end face 3804. In a particular aspect, depending on theorientation, the first end face 3802 may be a base surface and thesecond end face 3804 may be an upper surface. The shaped abrasive grain3800 may include a generally K shaped first side face 3806 extendingbetween the first end face 3802 and the second end face 3804. Further,the shaped abrasive grain 3800 may include a generally flat second sideface 3808 opposite the generally K shaped first side face 3806 andextending between the first end face 3802 and the second end face 3804.

As shown, the shaped abrasive grain 3800 may also include a third sideface 3810 extending between the first end face 3802 and the second endface 3804 and between the first side face 3806 and the second side face3808. Further, the shaped abrasive grain 3800 may include a fourth sideface 3812 extending between the first end face 3802 and the second endface 3804 opposite the third side face 3810.

FIG. 40 and FIG. 41 show a nineteenth embodiment of a shaped abrasivegrain 4000. As shown in FIG. 40 and FIG. 41, the shaped abrasive grain4000 may include a body 4001 that is generally prismatic with a firstend face 4002 and a second end face 4004. In a particular aspect,depending on the orientation, the first end face 4002 may be a basesurface and the second end face 4004 may be an upper surface. Further,the shaped abrasive grain 4000 may include a first side face 4010extending between the first end face 4002 and the second end face 4004.A second side face 4012 may extend between the first end face 4002 andthe second end face 4004 adjacent to the first side face 4010. As shown,the shaped abrasive grain 4000 may also include a third side face 4014extending between the first end face 4002 and the second end face 4004adjacent to the second side face 4012. Further, the shaped abrasivegrain 4000 may include a fourth side face 4016 extending between thefirst end face 4002 and the second end face 4004 adjacent to the thirdside face 4014 and the first side face 4010.

As depicted in FIG. 40 and FIG. 41, the shaped abrasive grain 4000 mayalso include a first edge 4020 between the first side face 4010 and thesecond side face 4012. The shaped abrasive grain 4000 may also include asecond edge 4022 between the second side face 4012 and the third sideface 4014. The shaped abrasive grain 4000 may include a third edge 4024between the third side face 4014 and the fourth side face 4016.Moreover, the shaped abrasive grain 4000 may include a fourth edge 4026between the fourth side face 4016 and the first side face 4010.

As shown, each end face 4002, 4004 the shaped abrasive grain 4000 may begenerally diamond shaped. Each side face 4010, 4012, 4014, 4016 may begenerally rectangular in shape. Further, the cross section of the shapedabrasive grain 4000 in a plane parallel to the end faces 4002, 4004 isgenerally diamond shaped. As shown, the shaped abrasive grain 4000 mayalso include a hole 4030 formed along a central longitudinal axis 4032.The hole 4030 may pass through the center of the shaped abrasive grain4000. Alternatively, the hole 4030 may be offset from the center of theshaped abrasive grain 4000 in any direction.

FIG. 42 and FIG. 43 illustrate a twentieth embodiment of a shapedabrasive grain that is generally designated 4200. As shown, the shapedabrasive grain 4200 may include a body 4201 that includes a generallycircular first end face 4202 and a generally circular second end face4204. In a particular aspect, depending on the orientation, the firstend face 4202 may be a base surface and the second end face 4204 may bean upper surface. In a particular aspect, a diameter of the second endface 4204 may be larger than a diameter of the first end face 4202.

As shown, the shaped abrasive grain 4200 may include continuous sideface 4206 between the first end face 4202 and the second end face 4204.Accordingly, the shaped abrasive grain 4200 is generallyfrusto-conically shaped. FIG. 42 and FIG. 43 further indicate that theshaped abrasive grain 4200 may include a generally cylindrical hole 4208formed along a central longitudinal axis 4210.

Referring now to FIG. 44 through FIG. 46, a twenty-first embodiment of ashaped abrasive grain is shown and is generally designated 4400. Theshaped abrasive grain 4400 may include a body 4401 that may include agenerally triangular first end face 4402 and a generally circular secondend face 4404. In a particular aspect, depending on the orientation, thefirst end face 4402 may be an upper surface and the second end face 4404may be a base surface.

Further, the shaped abrasive grain 4400 may include a first side face4410 extending between the first end face 4402 and the second end face4404. A second side face 4412 may extend between the first end face 4402and the second end face 4404 adjacent to the first side face 4410. Asshown, the shaped abrasive grain 4400 may also include a third side face4414 extending between the first end face 4402 and the second end face4404 adjacent to the second side face 4412 and the first side face 4410.

As depicted in FIG. 44 and FIG. 45, the shaped abrasive grain 4400 mayalso include a first edge 4420 between the first side face 4410 and thesecond side face 4412. The shaped abrasive grain 4400 may also include asecond edge 4422 between the second side face 4412 and the third sideface 4414. Further, the shaped abrasive grain 4400 may include a thirdedge 4424 between the third side face 4414 and the first side face 4412.

Referring now to FIG. 47 through FIG. 49, a twenty-second embodiment ofa shaped abrasive grain is shown and is generally designated 4700. Theshaped abrasive grain 4700 may include a body 4701 having a generallysquare first end face 4702 and a generally circular second end face4704. In a particular aspect, depending on the orientation, the firstend face 4702 may be an upper surface and the second end face 4704 maybe a base surface.

Further, the shaped abrasive grain 4700 may include a first side face4710 extending between the first end face 4702 and the second end face4704. A second side face 4712 may extend between the first end face 4702and the second end face 4704 adjacent to the first side face 4710. Asshown, the shaped abrasive grain 4700 may also include a third side face4714 extending between the first end face 4702 and the second end face4704 adjacent to the second side face 4712. The shaped abrasive grain4700 may also include a fourth side face 4716 adjacent to the third sideface 4714 and the first side face 4710.

As depicted in FIG. 47 and FIG. 48, the shaped abrasive grain 4700 mayalso include a first edge 4720 between the first side face 4710 and thesecond side face 4712. The shaped abrasive grain 4700 may also include asecond edge 4722 between the second side face 4712 and the third sideface 4714. Further, the shaped abrasive grain 4700 may include a thirdedge 4724 between the third side face 4714 and the fourth side face4716. Also, the shaped abrasive grain 4700 may include a fourth edge4726 between the fourth side face 4716 and the first side face 4710.

FIG. 50 through FIG. 52 show a twenty-third embodiment of a shapedabrasive grain that is generally designated 5000. The shaped abrasivegrain 5000 may include a body 5001 having a generally plus (+) shapedfirst end face 5002 and a generally circular second end face 5004. In aparticular aspect, depending on the orientation, the first end face 5002may be an upper surface and the second end face 5004 may be a basesurface.

Further, the shaped abrasive grain 5000 may include a first side face5010 extending between the first end face 5002 and the second end face5004. A second side face 5012 may extend between the first end face 5002and the second end face 5004 adjacent to the first side face 5010. Asshown, the shaped abrasive grain 5000 may also include a third side face5014 extending between the first end face 5002 and the second end face5004 adjacent to the second side face 5012. The shaped abrasive grain5000 may also include a fourth side face 5016 adjacent to the third sideface 5014 and the first side face 5010.

As depicted in FIG. 50 and FIG. 51, the shaped abrasive grain 5000 mayalso include a first void 5020 between the first side face 5010 and thesecond side face 5012. The shaped abrasive grain 5000 may also include asecond void 5022 between the second side face 5012 and the third sideface 5014. Further, the shaped abrasive grain 5000 may include a thirdvoid 5024 between the third side face 5014 and the fourth side face5016. Also, the shaped abrasive grain 5000 may include a fourth void5026 between the fourth side face 5016 and the first side face 5010.

FIG. 53 through FIG. 55 show a twenty-fourth embodiment of a shapedabrasive grain that is generally designated 5300. The shaped abrasivegrain 5300 may include a body 5301 having a generally plus (+) shapedfirst end face 5302 and a generally rounded plus (+) shaped end face5304. In a particular aspect, depending on the orientation, the firstend face 5302 may be an upper surface and the second end face 5304 maybe a base surface.

As shown, the shaped abrasive grain 5300 may include a first side face5310 extending between the first end face 5302 and the second end face5304. A second side face 5312 may extend between the first end face 5302and the second end face 5304 adjacent to the first side face 5310. Asshown, the shaped abrasive grain 5300 may also include a third side face5314 extending between the first end face 5302 and the second end face5304 adjacent to the second side face 5312. The shaped abrasive grain5300 may also include a fourth side face 5316 adjacent to the third sideface 5314 and the first side face 5310.

As depicted in FIG. 53 through FIG. 55, the shaped abrasive grain 5300may also include a first void 5320 between the first side face 5310 andthe second side face 5312. The shaped abrasive grain 5300 may alsoinclude a second void 5322 between the second side face 5312 and thethird side face 5314. Further, the shaped abrasive grain 5300 mayinclude a third void 5324 between the third side face 5314 and thefourth side face 5316. Also, the shaped abrasive grain 5300 may includea fourth void 5326 between the fourth side face 5316 and the first sideface 5310.

Referring now to FIG. 56 through FIG. 58, a twenty-fifth embodiment of ashaped abrasive grain is shown and is generally designated 5600. Theshaped abrasive grain 5600 may include a body 5601 having a generallycircular first end face 5602 and a generally triangular second end face5604. The second end face 5604 is relatively larger than the first endface 5602. In a particular aspect, depending on the orientation, thefirst end face 5602 may be an upper surface and the second end face 5604may be a base surface.

As depicted, the shaped abrasive grain 5600 may include a first sideface 5610 extending between the first end face 5602 and the second endface 5604. A second side face 5612 may extend between the first end face5602 and the second end face 5604 adjacent to the first side face 5610.As shown, the shaped abrasive grain 5600 may also include a third sideface 5614 extending between the first end face 5602 and the second endface 5604 adjacent to the second side face 5612 and the first side face5610.

As shown in FIG. 56 through FIG. 58, the shaped abrasive grain 5600 mayalso include a first edge 5620 between the first side face 5610 and thesecond side face 5612. The shaped abrasive grain 5600 may also include asecond edge 5622 between the second side face 5612 and the third sideface 5614. Further, the shaped abrasive grain 5600 may include a thirdedge 5624 between the third side face 5614 and the first side face 5612.

Referring to FIG. 59 through FIG. 61, a twenty-sixth embodiment of ashaped abrasive grain is shown and is generally designated 5900. Theshaped abrasive grain 5900 may include a body 5901 having a generallycircular first end face 5902 and a generally square second end face5904. In a particular aspect, the second end face 5904 is relativelylarger than the first end face 5902. In a particular aspect, dependingon the orientation, the first end face 5902 may be an upper surface andthe second end face 5904 may be a base surface.

Further, the shaped abrasive grain 5900 may include a first side face5910 extending between the first end face 5902 and the second end face5904. A second side face 5912 may extend between the first end face 5902and the second end face 5904 adjacent to the first side face 5910. Asshown, the shaped abrasive grain 5900 may also include a third side face5914 extending between the first end face 5902 and the second end face5904 adjacent to the second side face 5912. The shaped abrasive grain5900 may also include a fourth side face 5916 adjacent to the third sideface 5914 and the first side face 5910.

As depicted in FIG. 59 through FIG. 61, the shaped abrasive grain 5900may also include a first edge 5920 between the first side face 5910 andthe second side face 5912. The shaped abrasive grain 5900 may alsoinclude a second edge 5922 between the second side face 5912 and thethird side face 5914. Further, the shaped abrasive grain 5900 mayinclude a third edge 5924 between the third side face 5914 and thefourth side face 5916. Also, the shaped abrasive grain 5900 may includea fourth edge 5926 between the fourth side face 5916 and the first sideface 5910.

One or more of the shaped abrasive grains described herein areconfigured to land in an upright orientation when deposited onto abacking. Further, one or more of the embodiments described herein mayprovide a relatively high aspect ratio associated with a particularlength:height ratio, height:width ratio, length:width ratio,width:height ratio, height:length ratio, width:length ratio, or acombination thereof. A high aspect ratio enables the manufacture of acoated abrasive structure having an open coat, i.e., the distancebetween adjacent shaped abrasive grains may be increased. Further, theopen coat provides greater space for chip clearance and may lower powerconsumption by making a better cut, or grind.

Moreover, in bonded abrasive and thin wheel applications shaped abrasivegrains having high aspect ratios with sharp edges allows the manufactureof grinding wheels having greater porosity. Greater porosity providesmore space for swarf and chip clearance and may enable more coolant toflow through the grinding wheel to provide greater efficiency.

FIGS. 62A and B includes illustrations of a system for forming shapedabrasive particles in accordance with an embodiment. The process offorming shaped abrasive particles can be initiated by forming a mixture6201 including a ceramic material and a liquid. In particular, themixture 6201 can be a gel formed of a ceramic powder material and aliquid, wherein the gel can be characterized as a shape-stable materialhaving the ability to hold a given shape even in the green (i.e.,unfired) state. In accordance with an embodiment, the gel can include apowder material that is an integrated network of discrete particles.

The mixture 6201 can be formed to have a particular content of solidmaterial, such as the ceramic powder material. For example, in oneembodiment, the mixture 6201 can have a solids content of at least about25 wt %, such as at least about 35 wt %, at least about 38 wt %, or evenat least about 42 wt % for the total weight of the mixture 6201. Still,in at least one non-limiting embodiment, the solid content of themixture 6201 can be not greater than about 75 wt %, such as not greaterthan about 70 wt %, not greater than about 65 wt %, or even not greaterthan about 55 wt %. It will be appreciated that the content of thesolids materials in the mixture 6201 can be within a range between anyof the minimum and maximum percentages noted above.

According to one embodiment, the ceramic powder material can include anoxide, a nitride, a carbide, a boride, an oxycarbide, an oxynitride, anda combination thereof. In particular instances, the ceramic material caninclude alumina. More specifically, the ceramic material may include aboehmite material, which may be a precursor of alpha alumina. The term“boehmite” is generally used herein to denote alumina hydrates includingmineral boehmite, typically being Al2O3.H2O and having a water contenton the order of 15%, as well as psuedoboehmite, having a water contenthigher than 15%, such as 20-38% by weight. It is noted that boehmite(including psuedoboehmite) has a particular and identifiable crystalstructure, and accordingly unique X-ray diffraction pattern, and assuch, is distinguished from other aluminous materials including otherhydrated aluminas such as ATH (aluminum trihydroxide) a common precursormaterial used herein for the fabrication of boehmite particulatematerials.

Furthermore, the mixture 6201 can be formed to have a particular contentof liquid material. Some suitable liquids may include organic materials,such as water. In accordance with one embodiment, the mixture 6201 canbe formed to have a liquid content less than the solids content of themixture 6201. In more particular instances, the mixture 6201 can have aliquid content of at least about 25 wt % for the total weight of themixture 6201. In other instances, the amount of liquid within themixture 6201 can be greater, such as at least about 35 wt %, at leastabout 45 wt %, at least about 50 wt %, or even at least about 58 wt %.Still, in at least one non-limiting embodiment, the liquid content ofthe mixture can be not greater than about 75 wt %, such as not greaterthan about 70 wt %, not greater than about 65 wt %, not greater thanabout 60 wt %, or even not greater than about 55 wt %. It will beappreciated that the content of the liquid in the mixture 6201 can bewithin a range between any of the minimum and maximum percentages notedabove.

Furthermore, to facilitate processing and forming shaped abrasiveparticles according to embodiments herein, the mixture 6201 can have aparticular storage modulus. For example, the mixture 6201 can have astorage modulus of at least about 1×10⁴ Pa, such as at least about 4×10⁴Pa, or even at least about 5×10⁴ Pa. However, in at least onenon-limiting embodiment, the mixture 6201 may have a storage modulus ofnot greater than about 1×10⁷ Pa, such as not greater than about 1×10⁶Pa. It will be appreciated that the storage modulus of the mixture 6201can be within a range between any of the minimum and maximum valuesnoted above. The storage modulus can be measured via a parallel platesystem using ARES or AR-G2 rotational rheometers, with Peltier platetemperature control systems. For testing, the mixture 6201 can beextruded within a gap between two plates that are set to beapproximately 8 mm apart from each other. After extruding the get intothe gap, the distance between the two plates defining the gap is reducedto 2 mm until the mixture 6201 completely fills the gap between theplates. After wiping away excess mixture, the gap is decreased by 0.1 mmand the test is initiated. The test is an oscillation strain sweep testconducted with instrument settings of a strain range between 0.1% to100%, at 6.28 rad/s (1 Hz), using 25-mm parallel plate and recording 10points per decade. Within 1 hour after the test completes, lower the gapagain by 0.1 mm and repeat the test. The test can be repeated at least 6times. The first test may differ from the second and third tests. Onlythe results from the second and third tests for each specimen should bereported.

Furthermore, to facilitate processing and forming shaped abrasiveparticles according to embodiments herein, the mixture 6201 can have aparticular viscosity. For example, the mixture 6201 can have a viscosityof at least about 4×10³ Pa s, at least about 5×10³ Pa s, at least about6×10³ Pa s, at least about 8×10³ Pa s, at least about 10×10³ Pa s, atleast about 20×10³ Pa s, at least about 30×10³ Pa s, at least about40×10³ Pa s, at least about 50×10³ Pa s, at least about 60×10³ Pa s, oreven at least about 65×10³ Pa s. In at least one non-limitingembodiment, the mixture 6201 may have a viscosity of not greater thanabout 1×10⁶ Pa s, not greater than about 5×10⁵ Pa s, not greater thanabout 3×10⁵ Pa s, or even not greater than about 2×10⁵ Pa s. It will beappreciated that the viscosity of the mixture 6201 can be within a rangebetween any of the minimum and maximum values noted above. The viscositycan be calculated by dividing the storage modulus value by 6.28 s-1.

Moreover, the mixture 6201 can be formed to have a particular content oforganic materials, including for example, organic additives that can bedistinct from the liquid, to facilitate processing and formation ofshaped abrasive particles according to the embodiments herein. Somesuitable organic additives can include stabilizers, binders, such asfructose, sucrose, lactose, glucose, UV curable resins, and the like.

Notably, the embodiments herein may utilize a mixture 6201 that isdistinct from slurries used in conventional tape casting operations. Forexample, the content of organic materials within the mixture 6201,particularly, any of the organic additives noted above may be a minoramount as compared to other components within the mixture 6201. In atleast one embodiment, the mixture 6201 can be formed to have not greaterthan about 30 wt % organic material for the total weight of the mixture6201. In other instances, the amount of organic materials may be less,such as not greater than about 15 wt %, not greater than about 10 wt %,or even not greater than about 5 wt %. Still, in at least onenon-limiting embodiment, the amount of organic materials within themixture 6201 can be at least about 0.1 wt %, such as at least about 0.5wt % for the total weight of the mixture 6201. It will be appreciatedthat the amount of organic materials in the mixture 6201 can be within arange between any of the minimum and maximum values noted above.

Moreover, the mixture 6201 can be formed to have a particular content ofacid or base distinct from the liquid, to facilitate processing andformation of shaped abrasive particles according to the embodimentsherein. Some suitable acids or bases can include nitric acid, sulfuricacid, citric acid, chloric acid, tartaric acid, phosphoric acid,ammonium nitrate, ammonium citrate. According to one particularembodiment, the mixture 6201 can have a pH of less than about 5, andmore particularly, within a range between about 2 and about 4, using anitric acid additive.

Referencing FIG. 62, the system 6200 can include a die 6203. Asillustrated, the mixture 6201 can be provided within the interior of thedie 6203 and configured to be extruded through a die opening 6205positioned at one end of the die 6203. As further illustrated, formingcan include applying a force 6280 (that may be translated into apressure) on the mixture 6201 to facilitate moving the mixture 6201through the die opening 6205. In accordance with an embodiment, aparticular pressure may be utilized during extrusion. For example, thepressure can be at least about 10 kPa, such as at least about 500 kPa.Still, in at least one non-limiting embodiment, the pressure utilizedduring extrusion can be not greater than about 4 MPa. It will beappreciated that the pressure used to extrude the mixture 6201 can bewithin a range between any of the minimum and maximum values notedabove.

In certain systems, the die 6203 can include a die opening 6205 having aparticular shape. It will be appreciated that the die opening 6205 maybe shaped to impart a particular shape to the mixture 6201 duringextrusion. In accordance with an embodiment, the die opening 6205 canhave a rectangular shape. Furthermore, the mixture 6201 extruded throughthe die opening 6205 can have essentially the same cross-sectional shapeas the die opening 6205. As further illustrated, the mixture 6201 may beextruded in the form of a sheet 6211 and onto a belt 6209 underlying thedie 6203. In specific instances, the mixture 6201 can be extruded in theform of a sheet 6211 directly onto the belt 6209, which may facilitatecontinuous processing.

According to one particular embodiment, the belt can be formed to have afilm overlying a substrate, wherein the film can be a discrete andseparate layer of material configured to facilitate processing andforming of shaped abrasive particles. The process can include providingthe mixture 6201 directly onto the film of the belt to form the sheet6211. In certain instances, the film can include a polymer material,such as polyester. In at least one particular embodiment, the film canconsist essentially of polyester.

In some embodiments, the belt 6209 can be translated while moving themixture 6201 through the die opening 6205. As illustrated in the system6200, the mixture 6201 may be extruded in a direction 6291. Thedirection of translation 6210 of the belt 6209 can be angled relative tothe direction of extrusion 6291 of the mixture. While the angle betweenthe direction of translation 6210 and the direction of extrusion 6291are illustrated as substantially orthogonal in the system 6200, otherangles are contemplated, including for example, an acute angle or anobtuse angle. The belt 6209 may be translated at a particular rate tofacilitate processing. For example, the belt 6209 may be translated at arate of at least about 3 cm/s, such as at least about 4 cm/s, at leastabout 6 cm/s, at least about 8 cm/s, or even at least about 10 cm/s.Still, in at least one non-limiting embodiment, the belt 6209 may betranslated in a direction 6210 at a rate of not greater than about 5m/s, such as not greater than about 1 m/s, or even not greater thanabout 0.5 m/s. It will be appreciated that the belt 6209 may betranslated at a rate within a range between any of the minimum andmaximum values noted above.

For certain processes according to embodiments herein, the rate oftranslation of the belt 6209 as compared to the rate of extrusion of themixture 6201 in the direction 6291 may be controlled to facilitateproper processing. For example, the rate of translation of the belt 6209can be essentially the same as the rate of extrusion to ensure formationof a suitable sheet 6211.

After the mixture 6201 is extruded through the die opening 6205, themixture 6201 may be translated along the belt 6209 under a knife edge6207 attached to a surface of the die 6203. The knife edge 6207 mayfacilitate forming a sheet 6211. More particularly, the opening definedbetween the surface of the knife edge 6207 and belt 6209 may defineparticular dimensions of the extruded mixture 6201. For certainembodiments, the mixture 6201 may be extruded in the form of a sheet6211 having a generally rectangular cross-sectional shape as viewed in aplane defined by a height and width of the sheet 6211. While theextrudate is illustrated as a sheet, other shapes can be extruded,including for example cylindrical shapes and the like.

The process of forming the sheet 6211 from the mixture 6201 can includecontrol of particular features and process parameters to facilitatesuitable formation of shaped abrasive particles having one or morefeatures as provided in the embodiments herein. For example, in certaininstances, the process of forming a sheet 6211 from the mixture 6201 caninclude forming a sheet 6211 having a particular height 6281 controlledin part by a distance between the knife edge 6207 and a surface of thebelt 6209. Moreover, it is noted that the height 6281 of the sheet 6211can be controlled by varying a distance between the knife edge 6207 andthe surface of the belt 6209. Additionally, forming the mixture 6201into the sheet 6211 can include controlling the dimensions of the sheet6211 based in part upon the viscosity of the mixture 6201. Inparticular, forming the sheet 6211 can include adjusting the height 6281of the sheet 6211 based on the viscosity of the mixture 6201.

The sheet 6211 can have particular dimensions, including for example alength (l), a width (w), and a height (h). In accordance with anembodiment, the sheet 6211 may have a length that extends in thedirection of the translating belt 6209, which can be greater than thewidth, wherein the width of the sheet 6211 is a dimension extending in adirection perpendicular to the length of the belt 6209 and to the lengthof the sheet. The sheet 6211 can have a height 6281, wherein the lengthand width are greater than the height 6281 of the sheet 6211.

Notably, the height 6281 of the sheet 6211 can be the dimensionextending vertically from the surface of the belt 6209. In accordancewith an embodiment, the sheet 6211 can be formed to have a particulardimension of height 6281, wherein the height may be an average height ofthe sheet 6211 derived from multiple measurements. For example, theheight 6281 of the sheet 6211 can be at least about 0.1 mm, such as atleast about 0.5 mm. In other instances, the height 6281 of the sheet6211 can be greater, such as at least about 0.8 mm, at least about 1 mm,at least about 1.2 mm, at least about 1.6 mm, or even at least about 2mm. Still, in one non-limiting embodiment, the height 6281 of the sheet6211 may be not greater than about 10 mm, not greater than about 5 mm,or even not greater than about 2 mm. It will be appreciated that thesheet 6211 may have an average height within a range between any of theminimum and maximum values noted above.

According to one embodiment, the sheet 6211 can have a length (l), awidth (w), and a height (h), wherein the length≧width≧height. Moreover,the sheet 6211 can have a secondary aspect ratio of length:height of atleast about 10, such as at least about 100, at least about 1000, or evenat least about 1000.

After extruding the mixture 6201 from the die 6203, the sheet 6211 maybe translated in a direction 6212 along the surface of the belt 6209.Translation of the sheet 6211 along the belt 6209 may facilitate furtherprocessing to form precursor shaped abrasive particles. For example, thesheet 6211 may undergo a shaping process within the shaping zone 6213,which may In particular instances, the process of shaping can includeshaping a surface of the sheet 6211, including for example, an uppermajor surface 6217 of the sheet 6211, which may be completed using ashaping article 6215. In other embodiments, other major surfaces of thesheet may undergo shaping, including for example, the bottom surface orside surfaces. For certain processes, shaping can include altering acontour of the sheet through one or more processes, such as, embossing,rolling, cutting, engraving, patterning, stretching, twisting, and acombination thereof.

In accordance with an embodiment, the process of forming a shapedabrasive particle can further include translation of the sheet along thebelt 6209 through a forming zone 6221. In accordance with an embodiment,the process of forming a shaped abrasive particle can include sectioningthe sheet 6211 to form precursor shaped abrasive particles 6223. Forexample, in certain instances, forming can include perforating a portionof the sheet 6211. In other instances, the process of forming caninclude patterning the sheet 6211 to form a patterned sheet andextracting shapes from the patterned sheet.

Particular processes of forming can include cutting, pressing, punching,crushing, rolling, twisting, bending, drying, and a combination thereof.In one embodiment, the process of forming can include sectioning of thesheet 6211. Sectioning of the sheet 6211 can include the use of at leastone mechanical object, which may be in the form of a gas, liquid, orsolid material. The process of sectioning can include at least one or acombination of cutting, pressing, punching, crushing, rolling, twisting,bending, and drying. Moreover, it will be appreciated that sectioningcan include perforating or creating a partial opening through a portionof the sheet 6211, which may not extend through the entire height of thesheet 6211. In one embodiment, sectioning of the sheet 6211 can includeuse of a mechanical object including one or a plurality of a blade, awire, a disc, and a combination thereof.

The process of sectioning can create different types of shaped abrasiveparticles in a single sectioning process. Different types of shapedabrasive particles can be formed from the same processes of theembodiments herein. Different types of shaped abrasive particles includea first type of shaped abrasive particle having a first two-dimensionalshape and a second type of shaped abrasive particle having a differenttwo-dimensional shape as compared to the first two-dimensional shape.Furthermore, different types of shaped abrasive particles may differfrom each other in size. For example, different types of shaped abrasiveparticles may have different volumes as compared to each other. A singleprocess which is capable of forming different types of shaped abrasiveparticles may be particularly suited for producing certain types ofabrasive articles.

Sectioning can include moving the mechanical object through a portion ofa sheet 6211 and creating an opening within the sheet 6211. Inparticular, the sheet can be formed to have an opening extending intothe volume of the sheet and defined by certain surfaces. The opening candefine a cut extending through at least a fraction of the entire heightof sheet. It will be appreciated that the opening does not necessarilyneed to extend through the full height of the sheet. In certaininstances, the method of sectioning can include maintaining the openingin the sheet. Maintaining the opening after sectioning the sheet hasbeen sectioned by a mechanical object may facilitate suitable formationof shaped abrasive particles and features of shaped abrasive particlesand features of a batch of shaped abrasive particles. Maintaining theopening can include at least partially drying at least one surface ofthe sheet defining the opening. The process of at least partially dryingcan include directing a drying material at the opening. A dryingmaterial may include a liquid, a solid, or even a gas. According to oneparticular embodiment, the drying material can include air. Controlleddrying may facilitate the formation of shaped abrasive particlesaccording to embodiments herein.

In certain instances, the process of sectioning can be conducted priorto sufficient drying of the sheet. For example, sectioning can beconducted prior to volatilization of not greater than about 20% of theliquid from the sheet as compared to the original liquid content of thesheet during initial formation of the sheet. In other embodiments, theamount of volatilization allowed to occur before or during sectioningcan be less, such as, not greater than about 15%, not greater than about12%, not greater than about 10%, not greater than about 8%, or even notgreater than about 4% of the original liquid content of the sheet.

Referring again to FIGS. 62A and 62B, after forming precursor shapedabrasive particles 6223, the particles may be translated through apost-forming zone 6225. Various processes may be conducted in thepost-forming zone 6225, including for example, heating, curing,vibration, impregnation, doping, and a combination thereof.

In one embodiment, the post-forming zone 6225 includes a heatingprocess, wherein the precursor shaped abrasive particles 6223 may bedried. Drying may include removal of a particular content of material,including volatiles, such as water. In accordance with an embodiment,the drying process can be conducted at a drying temperature of notgreater than 300° C. such as not greater than 280° C. or even notgreater than about 250° C. Still, in one non-limiting embodiment, thedrying process may be conducted at a drying temperature of at least 50°C. It will be appreciated that the drying temperature may be within arange between any of the minimum and maximum temperatures noted above.

Furthermore, the precursor shaped abrasive particles 6223 may betranslated through a post-forming zone at a particular rate, such as atleast about 0.2 feet/min and not greater than about 8 feet/min.Furthermore, the drying process may be conducted for a particularduration. For example, the drying process may be not greater than aboutsix hours.

After the precursor shaped abrasive particles 6223 are translatedthrough the post-forming zone 6225, the particles may be removed fromthe belt 6209. The precursor shaped abrasive particles 6223 may becollected in a bin 6227 for further processing.

In accordance with an embodiment, the process of forming shaped abrasiveparticles may further comprise a sintering process. The sinteringprocess can be conducted after collecting the precursor shaped abrasiveparticles 6223 from the belt 6209. Sintering of the precursor shapedabrasive particles 6223 may be utilized to densify the particles, whichare generally in a green state. In a particular instance, the sinteringprocess can facilitate the formation of a high-temperature phase of theceramic material. For example, in one embodiment, the precursor shapedabrasive particles 6223 may be sintered such that a high-temperaturephase of alumina, such as alpha alumina is formed. In one instance, ashaped abrasive particle can comprise at least about 90 wt % alphaalumina for the total weight of the particle. In other instances, thecontent of alpha alumina may be greater, such that the shaped abrasiveparticle may consist essentially of alpha alumina.

FIG. 63 includes an illustration of a system for forming a shapedabrasive particle in accordance with an embodiment. In particular, thesystem 6300 can generally include a screen printing process of formingshaped abrasive particles. However, as noted herein, certain portions ofthe system may be modified to conduct a molding process. As illustrated,the system 6300 can include a screen 6351 configured to be translatedbetween rollers 6370 and 6371. It will be appreciated that the screen6351 can be translated over a greater number of rollers or other devicesif so desired. As illustrated, the system 6300 can include a belt 6309configured to be translated in a direction 6316 over rollers 6372 and6373. It will be appreciated that the belt 6309 may be translated over agreater number of rollers or other devices if so desired.

As illustrated, the system 6300 can further include a die 6303configured to conduct extrusion of a mixture 6301 contained within areservoir 6302 of the die 6303. The process of forming a shaped abrasiveparticles can be initiated by forming a mixture 6301 including a ceramicmaterial and a liquid as described herein.

The mixture 6301 can be provided within the interior of the die 6303 andconfigured to be extruded through a die opening 6305 positioned at oneend of the die 6303. As further illustrated, extruding can includeapplying a force (or a pressure) on the mixture 6301 to facilitateextruding the mixture 6301 through the die opening 6305. In accordancewith an embodiment, a particular pressure may be utilized duringextrusion. For example, the pressure can be at least about 10 kPa, suchas at least about 500 kPa. Still, in at least one non-limitingembodiment, the pressure utilized during extrusion can be not greaterthan about 4 MPa. It will be appreciated that the pressure used toextrude the mixture 6301 can be within a range between any of theminimum and maximum values noted above.

In particular instances, the mixture 6301 can be extruded through a dieopening 6305 at the end of the die 6303 proximate to the screen 6351.The screen 6351 may be translated in a direction 6353 at a particularrate to facilitate suitable processing. Notably, the screen 6351 can betranslated through the application zone 6383 including the die opening6305 to facilitate the formation of precursor shaped abrasive particles.The screen 6351 may be translated through the application zone at a rateof at least about 3 cm/s, such as at least about 4 cm/s, at least about6 cm/s, at least about 8 cm/s, or even at least about 10 cm/s. Still, inat least one non-limiting embodiment, the screen 6351 may be translatedin a direction 6353 at a rate of not greater than about 5 m/s, such asnot greater than about 1 m/s, or even not greater than about 0.5 m/s. Itwill be appreciated that the screen 6351 may be translated at a ratewithin a range between any of the minimum and maximum values notedabove.

Additionally, the belt 6309 can be translated in a direction 6316 at aparticular rate to facilitate suitable processing. For example, the belt6309 can be translated at a rate of at least about 3 cm/s, such as atleast about 4 cm/s, at least about 6 cm/s, at least about 8 cm/s, oreven at least about 10 cm/s. Still, in at least one non-limitingembodiment, the belt 6309 may be translated in a direction 6316 at arate of not greater than about 5 m/s, such as not greater than about 1m/s, or even not greater than about 0.5 m/s. It will be appreciated thatthe belt 6309 may be translated at a rate within a range between any ofthe minimum and maximum values noted above.

In accordance with a particular embodiment, the screen 6351 may betranslated at a particular rate as compared to the rate of translationof the belt 6309. For example, within the application zone 6383, thescreen 6351 may be translated at substantially the same rate oftranslation of the belt 6309. That is, the difference in rate oftranslation between the screen and the belt may be not greater thanabout 5%, such as not greater than about 3%, or even not greater thanabout 1% based on the rate of the translation of the screen 6351.

As illustrated, the system 6300 can include an application zone 6383,including the die opening 6305. Within the application zone 6383, themixture 6301 may be extruded from the die 6303 and directly onto thescreen 6351. More particularly, a portion of the mixture 6301 may beextruded from the die opening 6305, and further extruded through one ormore openings in the screen 6351 and onto the underlying belt 6309.

Referring briefly to FIG. 64, a portion of a screen 6451 is illustrated.As shown, the screen 6451 can include an opening 6452, and moreparticularly, a plurality of openings 6452. The openings can extendthrough the volume of the screen 6451, to facilitate passable of themixture 6301 through the openings and onto the belt 6309. In accordancewith an embodiment, the openings 6452 can have a two-dimensional shapeas viewed in a plane defined by the length (l) and width (w) of thescreen. While the openings 6452 are illustrated as having athree-pointed star two-dimensional shape, other shapes are contemplated.For example, the openings 6452 can have a two-dimensional shape such aspolygons, ellipsoids, numerals, Greek alphabet letters, Latin alphabetletters, Russian alphabet characters, complex shapes including acombination of polygonal shapes, and a combination thereof. Inparticular instances, the openings 6452 may have two-dimensionalpolygonal shapes such as, a triangle, a rectangle, a quadrilateral, apentagon, a hexagon, a heptagon, an octagon, a nonagon, a decagon, and acombination thereof. Moreover, a screen 6451 can be formed to include acombination of openings 6452 having a plurality of differenttwo-dimensional shapes.

Certain aspects of processing were found to facilitate the formation ofshaped abrasive particles according to embodiments herein. Notably, theorientation of the openings relative to the die head was found to havean effect on the shape of the shaped abrasive particles. In particular,it was noted, that when the openings are aligned as illustrated in FIG.64, wherein a point 6455 of the opening is first filled with the mixture6301 the shaped abrasive particles are suitably formed having thefeatures described herein. In other orientations, wherein for example, aside 6456 of the opening would be first filled, as opposed to a point(e.g., 6455) of the opening 6452, it was noted that the shaped abrasiveparticles had certain less suitable features.

Referring again to FIG. 63, after forcing the mixture 6301 through thedie opening 6305 and a portion of the mixture 6301 through the openings6352 in the screen 6351, precursor shaped abrasive particles 6353 may beprinted on a belt 6309 disposed under the screen 6351. According to aparticular embodiment, the precursor shaped abrasive particles 6353 canhave a shape substantially replicating the shape of the openings 6352.

After extruding the mixture 6301 into the openings 6352 of the screen6351, the belt 6309 and screen 6351 may be translated to a release zone6385, wherein the belt 6309 and screen 6351 can be separated tofacilitate the formation of precursor shaped abrasive particles. Inaccordance with an embodiment, the screen 6351 and belt 6309 may beseparated from each other within the release zone 6385 at a particularrelease angle 6355. In accordance with specific embodiment, the releaseangle 6355 can be a measure of the angle between a lower surface 6354 ofthe screen 6351 and an upper surface 6356 of the belt 6309.

Notably, the mixture 6301 can be forced through the screen 6351 in rapidfashion, such that the average residence time of the mixture 6301 withinthe openings 152 can be less than about 2 minutes, less than about 1minute, less than about 40 second, or even less than about 20 seconds.In particular non-limiting embodiments, the mixture 6301 may besubstantially unaltered during printing as it travels through the screenopenings 6352, thus experiencing no change in the amount of components,and may experience no appreciable drying in the openings 6352 of thescreen 6351.

In an alternative embodiment, the process of forming can include amolding process. The molding process may utilize some of the samecomponents of the system 6300, however, the screen can be replaced witha molding blank having openings within a substrate material for moldingthe mixture 6301. Notably, unlike a screen, the molding blank can haveopenings that extend partially through the entire thickness of theblank, such that the openings are not apertures extending from one majorsurface to the opposite major surface of the blank. Instead, the moldopenings can have a bottom surface within the interior volume, which areintended to form a major surface of the precursor shaped abrasiveparticle formed therein. Moreover, a molding system may not necessarilyutilize a belt underlying the molding blank.

The forming process may also utilize a particular drying process tofacilitate formation of shaped abrasive particles having features of theembodiments herein. In particular, the drying process may include dryingunder conditions including humidity, temperature, and atmosphericpressure and composition suitable for limiting distortions to the shapedabrasive particles.

It was found that unlike the formation of shaped abrasive particleshaving typical polygonal shapes, the process of forming complex shapes,particularly using replication processes, required control of one ormore process parameters, including drying conditions, amount and type oflubricant, pressure applied to the mixture during extrusion, material ofthe blank or belt, and the like. In particular instances, it was foundthat a belt or blank of stainless steel or polycarbonate polymer couldbe used. Moreover, it was found that the use of a natural oil material(e.g., canola oil) as a lubricant on the openings of the blank or beltmay facilitate improved forming of shaped abrasive particles.

The body of the shaped abrasive particles may include additives, such asdopants, which may be in the form of elements or compounds (e.g.,oxides). Certain suitable additives can include alkali elements,alkaline earth elements, rare-earth elements, hafnium (Hf), zirconium(Zr), niobium (Nb), tantalum (Ta), molybdenum (Mo), and a combinationthereof. In particular instances, the additive can include an elementsuch as lithium (Li), sodium (Na), potassium (K), magnesium (Mg),calcium (Ca), strontium (Sr), barium (Ba), scandium (Sc), yttrium (Y),lanthanum (La), cesium (Ce), praseodymium (Pr), niobium (Nb), hafnium(Hf), zirconium (Zr), tantalum (Ta), molybdenum (Mo), vanadium (V),chromium (Cr), cobalt (Co), iron (Fe), germanium (Ge), manganese (Mn),nickel (Ni), titanium (Ti), zinc (Zn), and a combination thereof.

The body of a shaped abrasive article may include a specific content ofadditive (e.g., dopant). For example, the body of a shaped abrasiveparticle may include not greater than about 12 wt % additive for thetotal weight of the body. In still other embodiments, they amount ofadditive may be less, such as not greater than about 11 wt %, notgreater than about 10 wt %, not greater than about 9 wt %, not greaterthan about 8 wt %, not greater than about 7 wt %, not greater than about6 wt %, or even not greater than about 5 wt %. Still, the amount ofadditive in at least one non-limiting embodiment can be at least about0.5 wt %, such as at least about 1 wt %, at least about 1.3 wt %, atleast about 1.8 wt %, at least about 2 wt %, at least about 2.3 wt %, atleast about 2.8 wt %, or even at least about 3 wt %. It will beappreciated that the amount of additive within a body of a shapedabrasive particle may be within a range between any of the minimum andmaximum percentages noted above.

FIG. 65A includes a top view image of a shaped abrasive particle formedaccording to a particular embodiment. As illustrated, the shapedabrasive particle 6500 can define a star-shaped body, as viewed in twodimensions. In particular, the shaped abrasive particle 6500 can includea body 6501 having a central portion 6502 and a first arm 6503, a secondarm 6504, and a third arm 6505 extending from the central portion 6502.The body 6501 can have a length (l) measured as the longest dimensionalong a side of the particle and a width (w), measured as the longestdimension of the particle between a midpoint 6553 of a side through themidpoint 6590 of the body 6501 to a first tip 6506 of the first arm6503. The width can extend in a direction perpendicular to the dimensionof the length. The body 6501 can have a height (h), extending in adirection perpendicular to the upper surface 6510 of the body 6501defining the third side surface 6556 between the upper surface and thebase surface 6511 as illustrated in FIG. 65B, which is a side viewillustration of the image of the particle of FIG. 65A.

The shaped abrasive particle 6500 can have a body 6501 in the form of athree-pointed star defined by the first arm 6503, second arm 6504, andthe third arm 6505 extending from the central portion 6502. According toone particular embodiment, at least one of the arms, including forexample, the first arm 6503, can have a midpoint width 6513 that is lessthan a central portion width 6512. The central portion 6502 can bedefined as a region between the midpoints 6551, 6552, and 6553 of thefirst side surface 6554, second side surface 6555, and third sidesurface 6556, respectively. The central portion width 6512 of the firstarm 6503 can be the width of the dimension between the midpoints 6551and 6552. The midpoint width 6513 can be the width of the line at amidpoint between the line of the central portion width 6510 and the tip6506 of the first arm 6503 along a first axis 6560. In certaininstances, the midpoint width 6513 can be not greater than about 90% ofthe central portion width 6512, such as not greater than about 80%, notgreater than about 70%, not greater than about 65%, or even not greaterthan about 60%. Still, the midpoint width 6513 can be at least about10%, such as at least about 20%, at least about 30%, or even at leastabout 40% of the central portion width 6510. It will be appreciated thatthe midpoint width 6513 can have a width relative to the central portionwidth 6512 within a range between any of the above minimum and maximumpercentages.

Moreover, the body 6501 can have at least one arm, such as the first arm6503, having a tip width 6514 at the tip 6506 of the first arm 6503 thatis less than a midpoint width 6513. In such instances wherein the tip6506 is sharply formed, the tip width 6514 may be considered 0. Ininstances wherein the tip 6506 has a radius of curvature, the tip width6514 may be considered the diameter of the circle defined by the radiusof cuvature. According to one embodiment, the tip width 6514 can be notgreater than about 90% of the midpoint width 6513, such as not greaterthan about 80%, not greater than about 70%, not greater than about 60%,not greater than about 50%, not greater than about 40%, not greater thanabout 30%, not greater than about 20%, or even not greater than about10%. Still, in certain non-limiting embodiments, the tip width 6514 canbe at least about 1%, such as at least about 2%, at least about 3%, atleast about 5%, or even at least about 10% of the midpoint width 6513.It will be appreciated that the tip width 6514 can have a width relativeto the midpoint width 6513 within a range between any of the aboveminimum and maximum percentages.

As further illustrated, the body 6501 can have a first arm 6503including a first tip 6506 defining a first tip angle 6521 between thefirst side surface 6554 and the second side surface 6555. According toan embodiment, the first tip angle can be less than about 60 degrees,such as not greater than about 55 degrees, not greater than about 50degrees, not greater than about 45 degrees, or even not greater thanabout 40 degrees. Still, the first tip angle can be at least about 5degrees, such as at least about 8 degrees, at least about 10 degrees, atleast about 15 degrees, at least about 20 degrees, at least about 25degrees, or even at least about 30 degrees. The first tip angle can bewithin a range between any of the minimum and maximum values notedabove.

The body 6501 can include a second arm 6504 having a second tip 6507defining a second tip angle 6522 between the second side surface 6555and third side surface 6556. The second tip angle can be substantiallythe same as the first tip angle, such as within 5% of the anglenumerical value. Alternatively, the second tip angle can besubstantially different relative to the first tip angle.

The body 6501 can include a third arm 6505 having a third tip 6508defining a third tip angle 6523 between the first side surface 6554 andthird side surface 6556. The third tip angle can be substantially thesame as the first tip angle or second tip angle, such as within 5% ofthe angle numerical value. Alternatively, the third tip angle can besubstantially different relative to the first tip angle or the secondtip angle.

The body 6501 can have a total angle, which is a sum of the value of thefirst tip angle, second tip angle, and third tip angle which can be lessthan about 180 degrees. In other embodiments, the total angle can be notgreater than about 175 degrees, such as not greater than about 170degrees, not greater than about 165 degrees, not greater than about 150degrees, such as not greater than about 140 degrees, not greater thanabout 130 degrees, not greater than about 125 degrees, or even notgreater than about 120 degrees. Still, in one non-limiting embodiment,the body 6501 can have a total angle of at least about 60 degrees, suchas at least about 70 degrees, at least about 80 degrees, at least about90 degrees, such as at least about 95 degrees, at least about 100degrees, or even at least about 105 degrees. It will be appreciated thatthe total sum angle can be within a range between any of the minimum andmaximum values noted above.

As noted herein, the body 6501 can have a first side surface 6554extending between the first arm 6506 and the third arm 6508. In certaininstances, the first side surface 6554 can have an arcuate contour. Forexample, turning briefly to FIG. 65C, a top view image of a shapedabrasive particle according to an embodiment is provided. Notably, theshaped abrasive particle of FIG. 65C can include a three-pointed starhaving a body 6581 and an arcuate side surface 6582 extending betweentwo points. In particular instances, the side surface 6582 can have aconcave contour defining a curved portion extending inward toward thecentral portion 6583 of the body 6581.

Referring again to FIG. 65A, the body 6501 can have a first side surface6554 having a first side section 6558 and a second side section 6559.The first side section 6558 can extend between the first tip 6506 andthe midpoint 6551 and the second side section 6559 can extend betweenthe third tip 6508 and the midpoint 6551. The first side section 6558and second side section 6559 can define an interior angle 6562 that canbe obtuse. For example, the interior angle 6562 can be greater thanabout 90 degrees, such as greater than about 95 degrees, greater thanabout 100 degrees, greater than about 110 degree, or even greater thanabout 120 degrees. Still, in one non-limiting embodiment, the interiorangle 6562 can be not greater than about 320 degrees, such as notgreater than about 300 degrees, or even not greater than about 270degrees. It will be appreciated that the interior angle can be within arange between any of the minimum and maximum values noted above.

The first side section 6558 can extend for a significant portion of thelength of the first side surface 6554. For example, the first sidesection 6558 can extend for at least about 20%, such as at least about25%, at least about 30%, at least about 35%, or even at least about 40%of a total length of the first side surface 6554. Still, in onenon-limiting embodiment, the first side section 6558 can have a length(ls1) between the midpoint 6551 and the first tip 6506 of not greaterthan about 80%, such as not greater than about 75%, not greater thanabout 70%, or even not greater than about 65% of the total length of theside surface 6554. It will be appreciated that the length of the firstside section 6558 can be within a range between any of the minimum andmaximum percentages noted above.

The second side section 6559 can extend for a significant portion of thelength of the first side surface 6554. For example, the second sidesection 6559 can extend for at least about 20%, such as at least about25%, at least about 30%, at least about 35%, or even at least about 40%of a total length of the first side surface 6554. Still, in onenon-limiting embodiment, the second side section 6559 can have a length(ls2) between the midpoint 6551 and the third tip 6508 of not greaterthan about 80%, such as not greater than about 75%, not greater thanabout 70%, or even not greater than about 65% of the total length of theside surface 6554 as a straight line between the first tip 6506 and thethird tip 6508. It will be appreciated that the length of the secondside section 6559 can be within a range between any of the minimum andmaximum percentages noted above.

The body 6501 can further include a fractured region 6570 on at least aportion of one side surface. For example, the body 6501 can have afractured region 6570 on a portion of the side surface 6554 between themidpoint 6551 and the third tip 6508. The fracture region 6570 can beintersecting at least a portion of an edge defining the base surface6511. Alternatively, or additionally, the fracture region 6570 can beintersecting at least a portion of an edge defining the upper surface6510. The fractured region can be characterized by having a surfaceroughness greater than a surface roughness of at least the upper surface6510 or the base surface 6511 of the body 6501. The fractured region6570 can define a portion of the body extending from the base surface6511. In certain instances, the fractured region 6570 can becharacterized by irregularly shaped protrusions and grooves extendingfrom the base surface 6511 along the first side surface 6554. In certaininstances, the fractured region 6570 can appear as and define a serratededge. A fracture region 6583 is also illustrated on the side surface6582 of the shaped abrasive particle of FIG. 65C.

In certain instances, the fracture region 6570 can be preferentiallylocated at or near the tips of the arms of the body. The fracturedregion 6570 can extend from the bottom surface 1703 and extendvertically for a fraction of the entire height of the side surface oreven for the entire height of the side surface.

While the foregoing body 6501 of the three-pointed star has been shownto have an upper surface 6510 having a two-dimensional shape, as viewedin the plane of the length and width of the body, that is substantiallythe same as the two-dimensional shape of the base surface 6511 of thebody 6501, other shapes are contemplated. For example, in oneembodiment, the cross-sectional shape of the body at the base surfacecan define a base surface shape from the group consisting of athree-pointed star, a four pointed star, a cross-shape, a polygon,ellipsoids, numerals, Greek alphabet characters, Latin alphabetcharacters, Russian alphabet characters, complex shapes having acombination of polygonal shapes, and a combination thereof. Moreover,the cross-sectional shape of the body at the upper surface can define anupper surface shape, which can be different than the base surface shapeand selected from the group of a three-pointed star, a four pointedstar, a cross-shape, a polygon, ellipsoids, numerals, Greek alphabetcharacters, Latin alphabet characters, Russian alphabet characters,complex shapes having a combination of polygonal shapes, and acombination thereof.

In particular instances, the upper surface shape can have an arcuateform of the base surface shape. For example, the upper surface shape candefine an arcuate three-pointed two-dimensional shape, wherein thearcuate three-pointed two-dimensional shape defines arms having roundedends. In particular, the arms as defined at the base surface can have asmaller radius of curvature at the tip as compared to the radius ofcurvature of the corresponding tip at the upper surface.

As described in other embodiments herein, it will be appreciated that atleast one of the arms of the body 6501 may be formed to have a twist,such that the arm twists around a central axis. For example, the firstarm 6503 may twist around the axis 6560. Moreover, the body 6501 can beformed such that at least one arm extends in an arcuate path from thecentral region.

FIG. 66A includes a top view image of a shaped abrasive particle formedaccording to a particular embodiment. As illustrated, the shapedabrasive particle 6600 can define a star-shaped body, as viewed in aplane defined by the two dimensions of length and width. In particular,the shaped abrasive particle 6600 can include a body 6601 having acentral portion 6602 and a first arm 6603, a second arm 6604, a thirdarm 6605, and a fourth arm 6606 extending from the central portion 6602.The body 6601 can have a length (l), measured as the longest dimensionalong a side of the particle and a width (w), and measured as thelongest dimension of the particle between two points of opposite armsand through the midpoint 6609 of the body 6601. The width can extend ina direction perpendicular to the dimension of the length. The body 6601can have a height (h), extending in a direction perpendicular to theupper surface 6610 of the body 6601 defining the third side surface 6656between the upper surface and the base surface 6611 as illustrated inFIG. 66B. Notably, the body 6601 can have more than one height as willbe described in more detail herein.

The shaped abrasive particle 6600 can have a body 6601 in the form of afour-pointed star defined by the first arm 6603, a second arm 6604, athird arm 6605, and the fourth arm 6606 extending from the centralportion 6602. The body 6601 can have any of the features described inthe embodiments herein. For example, according to one particularembodiment, at least one of the arms, including for example, the firstarm 6603, can have a midpoint width that is less than a central portionwidth, as described in accordance with the embodiment of FIG. 65A.Moreover, the body 6601 can have at least one arm, such as the first arm6603, having a tip width at the tip of the first arm that is less than amidpoint width as described in accordance with the embodiment of FIG.65A.

In one aspect, the body 6601 can have a first arm 6603 including a firsttip 6607 defining a first tip angle 6621 between the first side surface6654 and the second side surface 6655. According to an embodiment, thefirst tip angle can be less than about 60 degrees, such as not greaterthan about 55 degrees, not greater than about 50 degrees, not greaterthan about 45 degrees, or even not greater than about 40 degrees. Still,the first tip angle 6621 can be at least about 5 degrees, such as atleast about 8 degrees, at least about 10 degrees, at least about 15degrees, or even at least about 20 degrees. The first tip angle 6621 canbe within a range between any of the minimum and maximum values notedabove. Likewise, any of the other tips, including the second tip 6608 ofthe second arm 6604, the third tip 6609 of the third arm 6605, or fourthtip 6610 of the fourth arm 6606 can have a tip angle having the samefeatures described in accordance with the first tip angle 6621 above.

According to one embodiment the second tip 6608 can define a second tipangle that is substantially the same as the first tip angle 6621, suchas within 5% of the angle numerical value. Alternatively, the second tipangle can be substantially different relative to the first tip angle6621. The third tip 6609 can define a third tip angle that issubstantially the same as the first tip angle 6621, such as within 5% ofthe angle numerical value. Alternatively, the third tip angle can besubstantially different relative to the first tip angle 6621. The fourthtip 6610 can define a fourth tip angle that is substantially the same asthe first tip angle 6621, such as within 5% of the angle numericalvalue. Alternatively, the fourth tip angle can be substantiallydifferent relative to the first tip angle 6621.

According to one embodiment, the body 6601 can include a first arm 6603,second arm 6604, third arm 6605, and fourth arm 6606 that aresubstantially evenly spaced apart with respect to each other. Asillustrated, the arms 6603-6606 can be spaced substantially evenlyaround the central portion 6602. In one particular embodiment, the arms6603-6606 can be spaced apart from each other at substantiallyorthogonal angles relative to each other. In other embodiments, thefirst arm 6603 and second arm 6604 can be spaced apart from each otherbased on the spacing angle 6631 defined by the angle between the axis6690 extending between opposite tips 6609 and 6607 and through themidpoint 6609 relative to the axis 6691 extending between tips 6608 and6610 and through the midpoint 6609. The first arm 6603 and second arm6604 can be spaced apart from each other as define by the spacing angle6631 by at least about 45 degrees, such as at least about 60 degrees, oreven at least about 70 degrees. Still, in other embodiments, the spacingangle 6631 can be not greater than about 120 degrees, such as notgreater than about 110 degrees, or even approximately 90 degrees. Thespacing angle 6631 can be within a range between any of the minimum andmaximum values noted above.

In certain instances, the body 6601 can be formed such that at least oneside surface, such as the first side surface 6654 can have an arcuatecontour. In more particular embodiments, at least one side surface canhave a concave curvature for at least a portion of the length of theentire side surface.

In still another embodiment, at least one side surface of the body 6601,such as the first side surface 6654, can have a first section 6625 and asecond section 6626, which can be joined together at a first sidesurface midpoint 6627 and defining a first interior angle 6628.According to one embodiment, the first interior angle can be greaterthan about 90 degrees, such as greater than about 95 degrees, greaterthan about 100 degrees, greater than about 130 degrees, greater thanabout 160 degrees, greater than about 180 degrees, or even greater thanabout 210 degrees. Still, in one non-limiting embodiment, the firstinterior angle can be not greater than about 320 degrees, not greaterthan about 300 degrees, or even not greater than about 270 degrees. Thefirst interior angle can be within a range between any of the minimumand maximum values noted above. Moreover, the body can include a secondinterior angle 6629 at the second side surface 6655, a third interiorangle 6632 at the third side surface 6656, and a fourth interior angle6633 at the fourth side surface 6657. Each of the interior angles canhave the features described with respect to the first interior angle6628. Moreover, each and any of the second side surface 6655, the thirdside surface 6656, and the fourth side surface 6657 can have any of thefeatures of the first side surface 6654.

The body 6601 can have a first arm 6603 and the third arm 6605 extendingin opposite directions from the central portion 6602 of the body 6601relative to each other. Moreover, the second arm 6604 and the fourth arm6606 can extend in opposite directions relative to each other. Accordingto one embodiment, the second arm 6604 can have a length, as measuredbetween from the boundary of the central portion 6602 to the tip 6608along the axis 6691 that can be substantially the same as a length ofthe fourth arm 6606. In yet another instance, the second arm 6604 canhave a length that is substantially different than (e.g., less than orgreater than) a length of the first arm 6603 or third arm 6605.

While the foregoing body 6601 of the four-pointed star has been shown tohave an upper surface 6640 having a two-dimensional shape, as viewed inthe plane of the length and width of the body, that is substantially thesame as the two-dimensional shape of the base surface 6641 of the body6501, other shapes are contemplated. For example, in one embodiment, thecross-sectional shape of the body at the base surface can define a basesurface shape from the group consisting of a three-pointed star, a fourpointed star, a cross-shape, a polygon, ellipsoids, numerals, Greekalphabet characters, Latin alphabet characters, Russian alphabetcharacters, complex shapes having a combination of polygonal shapes, anda combination thereof. Moreover, the cross-sectional shape of the bodyat the upper surface can define an upper surface shape, which can bedifferent than the base surface shape and selected from the group of athree-pointed star, a four pointed star, a cross-shape, a polygon,ellipsoids, numerals, Greek alphabet characters, Latin alphabetcharacters, Russian alphabet characters, complex shapes having acombination of polygonal shapes, and a combination thereof.

In particular instances, the upper surface shape can have an arcuateform of the base surface shape. For example, the upper surface shape candefine an arcuate four-pointed two-dimensional shape, wherein thearcuate four-pointed two-dimensional shape defines arms having roundedends. In particular, the arms as defined at the base surface can have asmaller radius of curvature at the tip as compared to the radius ofcurvature of the corresponding tip at the upper surface.

According to one particular aspect, the body can be formed to havelimited deformation or warping of the body. For example, the body canhave a curling factor (ht/hi) of not greater than about 10, wherein thecurling factor is defined as a ratio between the greatest height of thebody at one tip of an arm (ht) as compared to a smallest dimension ofheight of the body at the interior (hi) (e.g., within the centralportion 6602). For example, turning to a side-view illustration of ashaped abrasive particle of FIG. 66B, the body 6601 can have an interiorheight, which represents the smallest height of the particle as viewedfrom the side. The greatest height (ht) of the body is represented bythe distance between the bottom surface (or plane of the bottom surface)and the highest point of the body 6601 as viewed from the side, whichcan be tip of a curled up arm. The shaped abrasive particles of theembodiments herein demonstrate limited warping, having a curling factorof not greater than about 5, not greater than about 3, not greater thanabout 2, not greater than about 1.8, not greater than about 1.7, notgreater than about 1.6, not greater than about 1.5, not greater thanabout 1.3, not greater than about 1.2, not greater than about 1.14, oreven not greater than about 1.10. Suitable computer programs, such asImageJ software, may be used to conduct an accurate analysis from imagesof the shaped abrasive particles to measure curling factor.

FIG. 67 includes a top view image of a shaped abrasive particle formedaccording to a particular embodiment. As illustrated, the shapedabrasive particle 6700 can define a cross-shaped body, as viewed in aplane defined by the two dimensions of length and width. In particular,the shaped abrasive particle 6700 can include a body 6701 having acentral portion 6702 and a first arm 6703, a second arm 6704, a thirdarm 6705, and a fourth arm 6706 extending from the central portion 6702.The body 6701 can have a length (l), measured as the longest dimensionalong a side of the particle and a width (w), and measured as thelongest dimension of the particle between two points of opposite armsand through the midpoint 6709 of the body 6701. The width can extend ina direction perpendicular to the dimension of the length. The body 6701can have a height (h), extending in a direction perpendicular to theupper surface 6710 of the body 6701 defining a side surface between theupper surface 6710 and the base surface 6711. The body 6701 can have anyone or a combination of features described in any of the embodimentsherein.

The body 6701 can have at least one arm, such as the first arm 6703having a midpoint width 6714 that is substantially the same as a centralportion width 6712 of the first arm 6703. Moreover, the length of thearm between points 6715 and 6716 on the axis 6790 defining the width ofthe body 6701 can be less than the width of the first arm 6703. Inparticular instances, the length can be not greater than about 90% ofthe width, such as not greater than about 80%, not greater than about70%, not greater than about 60%. Still, in one non-limiting embodiment,the length of the first arm 6703 can be at least about 10%, such as atleast about 20% of the width of the first arm 6703. The length can havea dimension relative to the width within a range between any of theminimum and maximum percentages noted above. Reference to the width ofthe first arm 6703 can be reference to the central portion width 6712,or midpoint width 6714. Any of the arms of the body 6701 can have thesame features of the first arm 6703.

FIG. 68 includes a top view image of a shaped abrasive particleaccording to an embodiment. As shown, the shaped abrasive particle 6800can define a generally cross-shaped body, as viewed in a plane definedby the two dimensions of length and width. In particular, the shapedabrasive particle 6800 can include a body 6801 having a central portion6802 and a first arm 6803, a second arm 6804, a third arm 6805, and afourth arm 6806 extending from the central portion 6802. The body 6801can have a length (l), measured as the longest dimension along a side ofthe particle and a width (w), and measured as the longest dimension ofthe particle between two points of opposite arms and through themidpoint 6809 of the body 6801. The width can extend in a directionperpendicular to the dimension of the length. The body 6801 can have aheight (h), extending in a direction perpendicular to the upper surface6810 of the body 6801 defining a side surface between the upper surface6810 and the base surface 6811. The body 6801 can have any one or acombination of features described in any of the embodiments herein.

In the particular embodiment of FIG. 68, the body can have a particularcombination of two-dimensional shapes of the base surface 6811 and theupper surface 6810. For example, the body can have a two-dimensionalshape (i.e., cross-sectional shape) of the body at the base surfacedefining a base surface shape, and a two-dimensional shape of the bodyat the upper surface defining an upper surface shape, and in particular,the base surface shape can be a generally cross-shaped the upper surfaceshape can be a rounded quadrilateral shape. The rounded quadrilateralshape can be defined by an upper surface 6810 (edges shown by the dottedline) that has four sides joined by rounded corners, wherein the cornersgenerally correspond to the arms of the cross-shape defined by the basesurface. Notably, the upper surface may not define arm portionsseparated by a side surface having at least two side surface sectionsangled with respect to each other, which are shown by the cross-shapedcontour of the base surface shape.

FIG. 69A includes an illustration of a side view of a shaped abrasiveparticle according to an embodiment. As illustrated, the shaped abrasiveparticle 6900 can include a body 6901 including a first layer 6902 and asecond layer 6903 overlying the first layer 6902. According to anembodiment, the body 6901 can have layers 6902 and 6903 that arearranged in a stepped configuration relative to each other. A steppedconfiguration can be characterized by at least one plateau region 6920on an upper surface 6910 of the first layer 6902 between a side surface6904 of the first layer 6902 and a side surface 6905 of the second layer6903. The size and shape of the plateau region 6920 may be controlled orpredetermined by one or more processing parameters and may facilitate animproved deployment of the abrasive particles into an abrasive articleand performance of the abrasive article.

In one embodiment, the plateau region 6902 can have a lateral distance6921, which can be defined as the greatest distance between an edge 6907between the upper surface 6910 of the first layer 6902 and a sidesurface 6904 of the first layer to the side surface 6905 of the secondlayer. Analysis of the lateral distance 6921 may be facilitated by atop-view image of the body 6901, such as shown in FIG. 69B. Asillustrated, the lateral distance 6921 can be the greatest distance ofthe plateau region 6902. In one embodiment, the lateral distance 6921may have a length that is less than the length 6910 of the first layer6902 (i.e., larger layer). In particular, the lateral distance 6921 canbe not greater than about 90%, such as not greater than about 80%, notgreater than about 70%, not greater than about 60%, not greater thanabout 50%, not greater than about 40%, not greater than about 30%, oreven not greater than about 20% of the length 6910 of the first layer6902 of the body 6901. Still, in one non-limiting embodiment, thelateral distance 6921 can have a length that is at least about 2%, atleast about 5%, at least about 8%, at least about 10%, at least about20%, at least about 25%, at least about 30%, or even at least about 50%of the length of the first layer 6902 of the body 6901. It will beappreciated that the lateral distance 6921 can have a length within arange between any of the minimum and maximum percentages noted above.

The second layer 6903 can have a particular length 6909, which is thelongest dimension of a side, such as shown in FIG. 69B, relative to alength 6910 of the first layer 6902 that may facilitate improveddeployment of the abrasive particles into an abrasive article and/orperformance of the abrasive article. For example, the length 6909 of thesecond layer 6903 can be not greater than about 90%, such as not greaterthan about 80%, not greater than about 70%, not greater than about 60%,not greater than about 50%, not greater than about 40%, not greater thanabout 30%, or even not greater than about 20% of the length 6910 of thefirst layer 6902 of the body 6901. Still, in one non-limitingembodiment, the second layer 6903 can have a length 69909 that can be atleast about 2%, at least about 10%, at least about 20%, at least about30%, at least about 40%, at least about 50%, at least about 60%, or evenat least about 70% of the length 6910 of the first layer 6902 of thebody 6901. It will be appreciated that the length 6909 of the secondlayer 6903 relative to the length 6910 of the first layer 6902 can bewithin a range between any of the minimum and maximum percentages notedabove.

The foregoing shaped abrasive particle of FIGS. 69A and 69B can beformed using a multiple sheets of material, multiple screens, and/ormultiple molding blanks. For example, one process can include the use ofa first screen, which is completely or partially filled with a firstmixture, and provision of a second screen, which can be different insize, shape or orientation with respect to the first screen, andprovision of a second mixture within the openings of the second screen.The second screen can be placed over the first screen or over precursorshaped abrasive particles formed from the first screen. The secondmixture can be provided on the precursor shaped abrasive particles ofthe first mixture to form precursor shaped abrasive particles having thestepped and layered configuration. Notably, the openings of the secondscreen can be smaller than the openings of the first screen. It will beappreciated that the first screen and second screen can have, but neednot necessarily utilize, different size openings, differenttwo-dimensional shapes of openings, and a combination thereof.

Moreover, in certain instances, the first screen and second screen canbe used at the same time as a composite screen to shape the mixture. Insuch instances, the first screen and second screen may be affixed toeach other to facilitate proper and continuous alignment between theopenings of the first screen and second screen. The second screen can beoriented on the first screen to facilitate alignment between theopenings in the first screen and openings in the second screens tofacilitate suitable delivery of the mixture into the openings of thefirst screen and second screen.

Still, the first screen and second screen may be used in separateprocesses. For example, wherein the first mixture is provided in thefirst screen at a first time and the second mixture is provided in thesecond screen at a second time. More particularly, the first mixture canbe provided in the openings of the first screen, and after the firstmixture has been formed in the openings of the first screen, the secondmixture can be provided on the first mixture. Such a process may beconducted while the first mixture is contained in the first openings ofthe first screen. In another instance, the first mixture may be removedfrom the openings of the first screen to create precursor shapedabrasive particles of the first mixture. Thereafter, the precursorshaped abrasive particles of the first mixture can be oriented withrespect to openings of the second screen, and the second mixture can beplaced in the openings of the second screen and onto the precursorshaped abrasive particles of the first mixture to facilitate formationof composite precursor shaped abrasive particles including the firstmixture and the second mixture. The same process may be used with onemold and one screen. Moreover, the same process may be completed usingfirst and second molds to form the first and second layers,respectively.

It will be appreciated that any of the characteristics of theembodiments herein can be attributed to a batch of shaped abrasiveparticles. A batch of shaped abrasive particles can include, but neednot necessarily include, a group of shaped abrasive particles madethrough the same forming process. In yet another instance, a batch ofshaped abrasive particles can be a group of shaped abrasive particles ofan abrasive article, such as a fixed abrasive article, and moreparticularly, a coated abrasive article, which may be independent of aparticular forming method, but having one or more defining featurespresent in a particular population of the particles. For example, abatch of particles may include an amount of shaped abrasive particlessuitable for forming a commercial grade abrasive product, such as atleast about 20 lbs. of particles.

Moreover, any of the features of the embodiments herein (e.g., aspectratio, multiple portions, number of arms, midpoint width to centralportion width, two-dimensional shape, curling factor, etc.) can be acharacteristic of a single particle, a median value from a sampling ofparticles of a batch, or an average value derived from analysis of asampling of particles from a batch. Unless stated explicitly, referenceherein to the characteristics can be considered reference to a medianvalue that is a based on a statistically significant value derived froma random sampling of suitable number of particles of a batch. Notably,for certain embodiments herein, the sample size can include at least 10,and more typically, at least 40 randomly selected particles from a batchof particles.

Any of the features described in the embodiments herein can representfeatures that are present in at least a portion of a batch of shapedabrasive particles. The portion may be a minority portion (e.g., lessthan 50% and any whole number integer between 1% and 49%) of the totalnumber of particles in a batch, a majority portion (e.g., 50% or greaterand any whole number integer between 50% and 99%) of the total number ofparticles of the batch, or even essentially all of the particles of abatch (e.g., between 99% and 100%). The provision of one or morefeatures of any shaped abrasive particle of a batch may facilitatealternative or improved deployment of the particles in an abrasivearticle and may further facilitate improved performance or use of theabrasive article.

A batch of particulate material can include a first portion including afirst type of shaped abrasive particle and a second portion including asecond type of shaped abrasive particle. The content of the firstportion and second portion within the batch may be controlled at leastin part based upon certain processing parameters. Provision of a batchhaving a first portion and a second portion may facilitate alternativeor improved deployment of the particles in an abrasive article and mayfurther facilitate improved performance or use of the abrasive article.

The first portion may include a plurality of shaped abrasive particles,wherein each of the particles of the first portion can havesubstantially the same features, including for example, but not limitedto, the same two-dimensional shape of a major surface. The batch mayinclude various contents of the first portion. For example, the firstportion may be present in a minority amount or majority amount. Inparticular instances, the first portion may be present in an amount ofat least about 1%, such as at least about 5%, at least about 10%, atleast about 20%, at least about 30%, at least about 40%, at least about50%, at least about 60%, or even at least about 70% for the totalcontent of portions within the batch. Still, in another embodiment, thebatch may include not greater than about 99%, such as not greater thanabout 90%, not greater than about 80%, not greater than about 70%, notgreater than about 60%, not greater than about 50%, not greater thanabout 40%, not greater than about 30%, not greater than about 20%, notgreater than about 10%, not greater than about 8%, not greater thanabout 6%, or even not greater than about 4% of the total portions withinthe batch. The batch can include a content of the first portion within arange between any of the minimum and maximum percentages noted above.

The second portion of the batch can include a plurality of shapedabrasive particles, wherein each of the shaped abrasive particles of thesecond portion can have substantially the same feature, including forexample, but not limited to, the same two-dimensional shape of a majorsurface. The second portion can have one or more features of theembodiments herein, which can be distinct compared to the plurality ofshaped abrasive particles of the first portion. In certain instances,the batch may include a lesser content of the second portion relative tothe first portion, and more particularly, may include a minority contentof the second portion relative to the total content of particles in thebatch. For example, the batch may contain a particular content of thesecond portion, including for example, not greater than about 40%, suchas not greater than about 30%, not greater than about 20%, not greaterthan about 10%, not greater than about 8%, not greater than about 6%, oreven not greater than about 4%. Still, in at least on non-limitingembodiment, the batch may contain at least about 0.5%, such as at leastabout 1%, at least about 2%, at least about 3%, at least about 4%, atleast about 10%, at least about 15%, or even at least about 20% of thesecond portion for the total content of portions within the batch. Itwill be appreciated that the batch can contain a content of the secondportion within a range between any of the minimum and maximumpercentages noted above.

Still, in an alternative embodiment, the batch may include a greatercontent of the second portion relative to the first portion, and moreparticularly, can include a majority content of the second portion forthe total content of particles in the batch. For example, in at leastone embodiment, the batch may contain at least about 55%, such as atleast about 60% of the second portion for the total portions of thebatch.

It will be appreciated that the batch can include other portions,including for example a third portion, comprising a plurality of shapedabrasive particles having a third feature that can be distinct from thefeatures of the particles of the first and second portions. The batchmay include various contents of the third portion relative to the secondportion and first portion. The third portion may be present in aminority amount or majority amount. In particular instances, the thirdportion may be present in an amount of not greater than about 40%, suchas not greater than about 30%, not greater than about 20%, not greaterthan about 10%, not greater than about 8%, not greater than about 6%, oreven not greater than about 4% of the total portions within the batch.Still, in other embodiments the batch may include a minimum content ofthe third portion, such as at least about 1%, such as at least about 5%,at least about 10%, at least about 20%, at least about 30%, at leastabout 40%, or even at least about 50%. The batch can include a contentof the third portion within a range between any of the minimum andmaximum percentages noted above. Moreover, the batch may include acontent of diluent, randomly shaped abrasive particles, which may bepresent in an amount the same as any of the portions of the embodimentsherein.

EXAMPLES Example 1

A mixture in the form of a gel is obtained having approximately 42%solids loading of boehmite commercially available as Catapal B fromSasol Corp. combined with 58 wt % water containing a minority content ofnitric acid and organic additives. The gel has a viscosity ofapproximately 3×10³ to 4×10⁴ Pa·s and a storage modulus of 3×10⁴ to2×10⁵ Pa.

The gel is extruded from a die using a pressure of up to 80 psi (552kPa) onto a mold blank of polycarbonate and into a plurality ofopenings, wherein each of the openings are in the shape of athree-pointed star. The surfaces of the openings within the mold blankhave been coated with canola oil. The openings define three-pointed startwo-dimensional shapes having a length of approximately 5-7 mm, a widthof 3-5 mm, and a depth of approximately 0.8 mm. The openings have tipangles of approximately 35 degrees, and an interior angle between thethree arms of approximately 225 degrees.

The gel is extruded into the openings and the gel is then dried forapproximately 24-48 hours in air under atmospheric conditions and withinthe mold to form precursor shaped abrasive particles. The precursorshaped abrasive particles were calcined in a box furnace atapproximately 600° C. for an 1 hour and then, the precursors shapedabrasive particles were sintered in a tube furnace up to 1320° C. for 3to 20 minutes. FIG. 65A is an image of a representative particle formedExample 1. The body has a curling factor of less than 5.

Example 2

The process of Example 1 was used with the exception that the mold blankutilized openings defining a four-point star shaped two-dimensionalshape having a length of approximately 7-9 mm, a width of 7-9 mm, and adepth of approximately 0.8 mm. The openings have tip angles ofapproximately 25 degrees, and an interior angle between the three armsof approximately 250 degrees. FIG. 66A is an image of a representativeparticle formed from Example 2. The body has a curling factor of lessthan 5.

Example 3

The process of Example 1 was used with the exception that the mold blankutilized openings defining a cross-shaped two-dimensional shape having alength of approximately 5-6 mm, a width of 5-6 mm, and a depth ofapproximately 0.8 mm. The arms have a width of approximately 2 mm and alength of approximately 1 mm. FIG. 67 is an image of a representativeparticle formed from Example 3. The body has a curling factor of lessthan 5.

The present application represents a departure from the state of theart. While the industry has recognized that shaped abrasive particlesmay be formed through processes such as molding and screen printing, theprocesses of the embodiments herein are distinct from such processes.Moreover, the resulting shaped abrasive particles have one or acombination of distinct features from particles formed according toconventional approaches. The shaped abrasive particles of theembodiments herein can have a particular combination of featuresdistinct from other conventional particles including, but not limitedto, aspect ratio, composition, additives, two-dimensional shape,three-dimensional shape, stepped configuration, curling factor, tipangles, interior angles, and the like. Notably, the embodiments hereininclude a combination of features facilitating the formation of batchesof shaped abrasive particle having particular features. And in fact, oneor more such features facilitate alternative deployment of the particlesin abrasive articles, and further, may facilitate improved performancein the context of fixed abrasives, such as bonded abrasives or coatedabrasives.

The above-disclosed subject matter is to be considered illustrative, andnot restrictive, and the appended claims are intended to cover all suchmodifications, enhancements, and other embodiments, which fall withinthe true scope of the present invention. Thus, to the maximum extentallowed by law, the scope of the present invention is to be determinedby the broadest permissible interpretation of the following claims andtheir equivalents, and shall not be restricted or limited by theforegoing detailed description.

The Abstract of the Disclosure is provided to comply with Patent Law andis submitted with the understanding that it will not be used tointerpret or limit the scope or meaning of the claims. In addition, inthe foregoing Detailed Description, various features may be groupedtogether or described in a single embodiment for the purpose ofstreamlining the disclosure. This disclosure is not to be interpreted asreflecting an intention that the claimed embodiments require morefeatures than are expressly recited in each claim. Rather, as thefollowing claims reflect, inventive subject matter may be directed toless than all features of any of the disclosed embodiments. Thus, thefollowing claims are incorporated into the Detailed Description, witheach claim standing on its own as defining separately claimed subjectmatter.

1.-17. (canceled)
 18. A shaped abrasive particle comprising: a body having a length (l), a width (w), and a height (h), wherein the body comprises a base surface end, an upper surface, and a side surface extending between the base surface and the upper surface, wherein the base surface comprises a different cross-sectional shape than a cross-sectional shape of the upper surface. 19.-20. (canceled)
 21. The shaped abrasive particle of claim 18, wherein the body comprises a three-pointed star having three arms extending from a central portion of the body, and wherein at least one of the arms comprises a midpoint width that is less than a central portion width. 22.-23. (canceled)
 24. The shaped abrasive particle of claim 21, wherein the base surface defines a three-pointed star two-dimensional shape, and wherein the upper surface comprises an arcuate three-pointed two-dimensional shape. 25.-29. (canceled)
 30. The shaped abrasive particle of claim 21, wherein the first side surface comprises a first section and a second section joined together at an interior angle, wherein the interior angle defines an angle greater than about 90 degrees. 31.-33. (canceled)
 34. The shaped abrasive particle of claim 18, wherein the side surface comprises a fractured region intersecting at least a portion of an edge defining the base surface. 35.-37. (canceled)
 38. The shaped abrasive particle of claim 21, wherein at least one arm comprises a twist.
 39. The shaped abrasive particle of claim 21, wherein the body comprises a curling factor of not greater than about 10, wherein the curling factor is defined as a ratio between the greatest height of the body at one tip of an arm (ht) as compared to a smallest dimension of height of the body at the interior (hi).
 40. (canceled)
 41. The shaped abrasive particle of claim 18, wherein the body comprises a four-pointed star comprising four arms extending from a central portion of the body, and wherein at least one of the arms comprises a midpoint width that is less than a central portion width.
 42. The shaped abrasive particle of claim 39, wherein the midpoint width is not greater than about 90% of the central width.
 43. The shaped abrasive particle of claim 39, wherein the base surface defines a four-pointed star two-dimensional shape, and wherein the upper surface comprises an arcuate four-pointed two-dimensional shape.
 44. The shaped abrasive particle of claim 39, wherein the four-pointed star comprises a first arm, a second arm, a third arm, and a fourth arm, wherein the first arm defines a first arm angle less than about 60 degrees.
 45. The shaped abrasive particle of claim 42, wherein the first arm, second arm, third arm, and fourth arm are substantially evenly spaced apart.
 46. The shaped abrasive particle of claim 42, wherein the body further comprises a first side surface extending between the first arm and the second arm and between the base surface and upper surface, and wherein the first side surface comprises an arcuate contour.
 47. The shaped abrasive particle of claim 44, wherein the first side surface comprises a first section and a second section joined together at a first interior angle, wherein the first interior angle defines an angle greater than about 90 degrees.
 48. (canceled)
 49. The shaped abrasive particle of claim 42, wherein the four-pointed star comprises a first arm, a second arm, a third arm, and a fourth arm, wherein the first arm and the third arm extend in opposite directions from the central portion of the body, wherein the second arm and the fourth arm extend in opposite directions relative to each other, wherein the second arm has a length substantially the same as the fourth arm, and wherein the second arm comprises a length substantially less than a length of the first arm.
 50. The shaped abrasive particle of claim 18, the body comprises a cross-shaped two-dimensional shape having a first arm, a second arm, a third arm, and a fourth arm extending from a central portion of the body, and wherein the first arm comprises a midpoint width that is substantially the same as a central portion width of the first arm. 51.-55. (canceled)
 56. A shaped abrasive particle comprising: a body having a length (l), a width (w), and a height (h), wherein the body comprises a three-pointed star having a first arm defining a first arm, a second arm defining a second arm, and a third arm defining a second arm, and wherein the first arm, second arm and third arm define a total angle of less than about 180 degrees; and wherein the body comprises a curling factor of not greater than about 10, wherein the curling factor is defined as a ratio between the greatest height of the body at one tip of an arm (ht) as compared to a smallest dimension of height of the body at the interior (hi).
 57. A shaped abrasive particle comprising: a body having a length (l), a width (w), and a height (h), wherein the body comprises a four-pointed star having a first arm, second arm, third arm, and fourth arm extending from a central portion; and wherein the body comprises a curling factor of not greater than about 10, wherein the curling factor is defined as a ratio between the greatest height of the body at one tip of an arm (ht) as compared to a smallest dimension of height of the body at the interior (hi).
 58. The shaped abrasive particle of any one of claims 56 and 57, wherein at least one of the arms comprises a midpoint width that is less than a central portion width. 59.-63. (canceled)
 64. The shaped abrasive particle of any one of claims 56 and 57, wherein the body further comprises a first side surface extending between the first arm and the second arm and between the base surface and upper surface, and wherein the first side surface comprises an arcuate contour. 65.-70. (canceled) 